diff --git a/Packages/AudioPlayer/README.md b/Packages/AudioPlayer/README.md
index 67ac8ee..5162c46 100644
--- a/Packages/AudioPlayer/README.md
+++ b/Packages/AudioPlayer/README.md
@@ -1,3 +1,57 @@
 # AudioPlayer
 ![Unity 2019.4+](https://img.shields.io/badge/unity-unity%202019.4%2B-blue)
 ![License: MIT](https://img.shields.io/badge/License-MIT-brightgreen.svg)
+
+## Introduction
+
+### Initialize
+
+```c#
+// One time Initialize
+AudioPlayer.Instance.Initialize();
+```
+
+### Play Bgm
+
+#### Simple play
+```c#
+AudioPlayer.Instance.Bgm.Play(audioClip);
+```
+
+#### Cross Fade
+```c#
+AudioPlayer.Instance.Bgm.CrossFade(audioClip, crossFadeTime: 3f);
+```
+
+### Play Sound effects
+```c#
+AudioPlayer.Instance.Se.Play(audioClip);
+```
+
+### Volume settings
+
+#### Change the volumes
+```c#
+// Master volume
+AudioPlayer.Instance.SetMasterVolume(0.5f);
+
+// Bgm volume
+AudioPlayer.Instance.Bgm.SetVolume(1f); // ActualVolume 0.5f
+
+// Se volume
+AudioPlayer.Instance.Se.SetVolume(0.5f); // ActualVolume 0.25f
+```
+
+The actual volume of the BGM will be `0.5 x 1 = 0.5f`.  
+The actual volume of the SE will be `0.5 x 0.5 = 0.25f`.
+
+## Installation
+
+### Installing from a Git URL
+1. Copy for `https://github.com/kameffee/AudioPlayer.git`
+2. Open a PackageManager. `Window/PackageManager`
+3. Click the add **[+]** button in the status bar.
+4. Select Add package from git URL from the add menu.
+5. Enter a valid Git URL in the text box and click Add.
+
+see for [Installing from a Git URL](https://docs.unity3d.com/2019.4/Documentation/Manual/upm-ui-giturl.html)
diff --git a/Packages/AudioPlayer/Runtime/AudioPlayer.cs b/Packages/AudioPlayer/Runtime/AudioPlayer.cs
index ce2ee03..5258d4e 100644
--- a/Packages/AudioPlayer/Runtime/AudioPlayer.cs
+++ b/Packages/AudioPlayer/Runtime/AudioPlayer.cs
@@ -3,9 +3,9 @@
 
 namespace Kameffee.AudioPlayer
 {
-    public class AudioPlayer
+    public sealed class AudioPlayer : IAudioPlayer
     {
-        public static AudioPlayer Instance
+        public static IAudioPlayer Instance
         {
             get
             {
@@ -21,28 +21,13 @@ public static AudioPlayer Instance
 
         private static AudioPlayer _instance;
 
-        public BgmManager Bgm => _bgmManager;
+        public IBgmPlayer Bgm => _bgmManager;
         private BgmManager _bgmManager;
 
-        public SeManager Se => _seManager;
+        public ISePlayer Se => _seManager;
         private SeManager _seManager;
 
-        public float MasterVolume
-        {
-            get => _masterVolume;
-            set
-            {
-                var toVolume = Mathf.Clamp01(value);
-                bool isChange = Math.Abs(toVolume - _masterVolume) > 0.000001f;
-                _masterVolume = toVolume;
-
-                if (isChange)
-                {
-                    OnChangeMasterVolume?.Invoke(toVolume);
-                }
-            }
-        }
-
+        public float MasterVolume => _masterVolume;
         private float _masterVolume;
 
         public event Action<float> OnChangeMasterVolume = null;
@@ -88,5 +73,17 @@ public void InitializeSe()
             _seManager = SeManager.Create();
             _seManager.Initialize();
         }
+
+        public void SetMasterVolume(float volume)
+        {
+            var toVolume = Mathf.Clamp01(volume);
+            bool isChange = Math.Abs(toVolume - _masterVolume) > 0.000001f;
+            _masterVolume = toVolume;
+
+            if (isChange)
+            {
+                OnChangeMasterVolume?.Invoke(toVolume);
+            }
+        }
     }
 }
diff --git a/Packages/AudioPlayer/Runtime/BgmManager.cs b/Packages/AudioPlayer/Runtime/BgmManager.cs
index b667b62..cc20c35 100644
--- a/Packages/AudioPlayer/Runtime/BgmManager.cs
+++ b/Packages/AudioPlayer/Runtime/BgmManager.cs
@@ -6,7 +6,7 @@
 
 namespace Kameffee.AudioPlayer
 {
-    public class BgmManager : MonoBehaviour
+    public sealed class BgmManager : MonoBehaviour, IBgmPlayer
     {
         private static readonly string ManagerName = "BgmManager";
         private static readonly string PlayerName = "BgmPlayer";
@@ -15,6 +15,8 @@ public class BgmManager : MonoBehaviour
 
         private int _preInstanceCount = 2;
 
+        public bool IsPlaying => _bgmPlayers.Any(bgmAudio => bgmAudio.IsPlaying);
+
         public float Volume => _volume;
         private float _volume;
 
diff --git a/Packages/AudioPlayer/Runtime/BgmPlayer.cs b/Packages/AudioPlayer/Runtime/BgmPlayer.cs
index e6f0c26..1fc54c8 100644
--- a/Packages/AudioPlayer/Runtime/BgmPlayer.cs
+++ b/Packages/AudioPlayer/Runtime/BgmPlayer.cs
@@ -10,7 +10,7 @@ public enum PlayType
     }
 
     [AddComponentMenu("Audio/Bgm Player")]
-    public class BgmPlayer : MonoBehaviour
+    public sealed class BgmPlayer : MonoBehaviour
     {
         [SerializeField]
         private PlayType _playType;
@@ -121,4 +121,4 @@ public void Stop(float fadeOutTime)
             AudioPlayer.Instance.Bgm.Stop(fadeOutTime, _ignoreTimeScale);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Packages/AudioPlayer/Runtime/BgmSlider.cs b/Packages/AudioPlayer/Runtime/BgmSlider.cs
index e799baf..27e98cc 100644
--- a/Packages/AudioPlayer/Runtime/BgmSlider.cs
+++ b/Packages/AudioPlayer/Runtime/BgmSlider.cs
@@ -4,7 +4,7 @@
 namespace Kameffee.AudioPlayer
 {
     [AddComponentMenu("UI/Audio/Bgm Slider")]
-    public class BgmSlider : MonoBehaviour
+    public sealed class BgmSlider : MonoBehaviour
     {
         [SerializeField]
         private Slider bgmSlider;
@@ -25,4 +25,4 @@ private void SetVolume(float volume)
             AudioPlayer.Instance.Bgm.SetVolume(volume);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Packages/AudioPlayer/Runtime/CoreBgmAudio.cs b/Packages/AudioPlayer/Runtime/CoreBgmAudio.cs
index caf7354..8886ba3 100644
--- a/Packages/AudioPlayer/Runtime/CoreBgmAudio.cs
+++ b/Packages/AudioPlayer/Runtime/CoreBgmAudio.cs
@@ -5,7 +5,7 @@
 namespace Kameffee.AudioPlayer
 {
     [AddComponentMenu("")]
-    public class CoreBgmAudio : MonoBehaviour
+    public sealed class CoreBgmAudio : MonoBehaviour
     {
         public AudioSource AudioSource
         {
@@ -156,4 +156,4 @@ public void SetVolume(float volume)
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Packages/AudioPlayer/Runtime/CoreSeAudio.cs b/Packages/AudioPlayer/Runtime/CoreSeAudio.cs
index 675771f..bde5695 100644
--- a/Packages/AudioPlayer/Runtime/CoreSeAudio.cs
+++ b/Packages/AudioPlayer/Runtime/CoreSeAudio.cs
@@ -3,7 +3,7 @@
 namespace Kameffee.AudioPlayer
 {
     [AddComponentMenu("")]
-    public class CoreSeAudio : MonoBehaviour
+    public sealed class CoreSeAudio : MonoBehaviour
     {
         public AudioSource AudioSource
         {
@@ -48,4 +48,4 @@ public void SetVolume(float volume)
             AudioSource.volume = volume;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Packages/AudioPlayer/Runtime/IAudioPlayer.cs b/Packages/AudioPlayer/Runtime/IAudioPlayer.cs
new file mode 100644
index 0000000..58b5246
--- /dev/null
+++ b/Packages/AudioPlayer/Runtime/IAudioPlayer.cs
@@ -0,0 +1,21 @@
+using System;
+
+namespace Kameffee.AudioPlayer
+{
+    public interface IAudioPlayer
+    {
+        float MasterVolume { get; }
+
+        bool Initialized { get; }
+
+        event Action<float> OnChangeMasterVolume;
+
+        IBgmPlayer Bgm { get; }
+
+        ISePlayer Se { get; }
+
+        void Initialize();
+
+        void SetMasterVolume(float volume);
+    }
+}
diff --git a/Packages/AudioPlayer/Runtime/IAudioPlayer.cs.meta b/Packages/AudioPlayer/Runtime/IAudioPlayer.cs.meta
new file mode 100644
index 0000000..0020492
--- /dev/null
+++ b/Packages/AudioPlayer/Runtime/IAudioPlayer.cs.meta
@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: d1ae51d63a6a470d96300af3665bfa93
+timeCreated: 1641773829
\ No newline at end of file
diff --git a/Packages/AudioPlayer/Runtime/IBgmPlayer.cs b/Packages/AudioPlayer/Runtime/IBgmPlayer.cs
new file mode 100644
index 0000000..70e5f39
--- /dev/null
+++ b/Packages/AudioPlayer/Runtime/IBgmPlayer.cs
@@ -0,0 +1,30 @@
+using System;
+using UnityEngine;
+
+namespace Kameffee.AudioPlayer
+{
+    public interface IBgmPlayer
+    {
+        bool IsPlaying { get; }
+
+        float Volume { get; }
+
+        event Action<float> OnChangeVolume;
+
+        void Play(int id, float pitch = 1, float fadeTime = 0f, bool ignoreTimeScale = false);
+
+        void Play(AudioClip audioClip, float pitch = 1, float fadeTime = 0f, bool ignoreTimeScale = false);
+
+        void CrossFade(int id, float crossFadeTime, float pitch = 1, bool ignoreTimeScale = false);
+
+        void CrossFade(AudioClip audioClip, float crossFadeTime, float pitch = 1, bool ignoreTimeScale = false);
+
+        void Stop(float fadeTime = 0f, bool ignoreTimeScale = false);
+
+        void Pause();
+
+        void UnPause();
+
+        void SetVolume(float volume);
+    }
+}
diff --git a/Packages/AudioPlayer/Runtime/IBgmPlayer.cs.meta b/Packages/AudioPlayer/Runtime/IBgmPlayer.cs.meta
new file mode 100644
index 0000000..768727d
--- /dev/null
+++ b/Packages/AudioPlayer/Runtime/IBgmPlayer.cs.meta
@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 0cb357055f684b29b18d2d073f6a91ed
+timeCreated: 1641774877
\ No newline at end of file
diff --git a/Packages/AudioPlayer/Runtime/ISePlayer.cs b/Packages/AudioPlayer/Runtime/ISePlayer.cs
new file mode 100644
index 0000000..7cb0be5
--- /dev/null
+++ b/Packages/AudioPlayer/Runtime/ISePlayer.cs
@@ -0,0 +1,18 @@
+using System;
+using UnityEngine;
+
+namespace Kameffee.AudioPlayer
+{
+    public interface ISePlayer
+    {
+        float Volume { get; }
+
+        event Action<float> OnChangeVolume;
+
+        void Play(AudioClip audioClip, float pitch = 1f);
+
+        void Stop();
+
+        void SetVolume(float volume);
+    }
+}
\ No newline at end of file
diff --git a/Packages/AudioPlayer/Runtime/ISePlayer.cs.meta b/Packages/AudioPlayer/Runtime/ISePlayer.cs.meta
new file mode 100644
index 0000000..2fbbaa8
--- /dev/null
+++ b/Packages/AudioPlayer/Runtime/ISePlayer.cs.meta
@@ -0,0 +1,3 @@
+fileFormatVersion: 2
+guid: 7f0c52147bd84f9b9a44ba51b3341f9b
+timeCreated: 1641774775
\ No newline at end of file
diff --git a/Packages/AudioPlayer/Runtime/SeManager.cs b/Packages/AudioPlayer/Runtime/SeManager.cs
index df8fb84..bb4eb7f 100644
--- a/Packages/AudioPlayer/Runtime/SeManager.cs
+++ b/Packages/AudioPlayer/Runtime/SeManager.cs
@@ -4,7 +4,7 @@
 
 namespace Kameffee.AudioPlayer
 {
-    public class SeManager : MonoBehaviour
+    public sealed class SeManager : MonoBehaviour, ISePlayer
     {
         private static readonly string SeManagerName = "SeManager";
         private static readonly string SePlayerName = "SePlayer";
diff --git a/Packages/AudioPlayer/Runtime/SePlayer.cs b/Packages/AudioPlayer/Runtime/SePlayer.cs
index 14612c8..e961c60 100644
--- a/Packages/AudioPlayer/Runtime/SePlayer.cs
+++ b/Packages/AudioPlayer/Runtime/SePlayer.cs
@@ -3,7 +3,7 @@
 namespace Kameffee.AudioPlayer
 {
     [AddComponentMenu("Audio/Se Player")]
-    public class SePlayer : MonoBehaviour
+    public sealed class SePlayer : MonoBehaviour
     {
         [SerializeField]
         private AudioClip _clip;
@@ -34,4 +34,4 @@ public void Play(AudioClip audioClip)
             AudioPlayer.Instance.Se.Play(audioClip, _pitch);
         }
     }
-}
\ No newline at end of file
+}
diff --git a/Packages/AudioPlayer/Runtime/SeSlider.cs b/Packages/AudioPlayer/Runtime/SeSlider.cs
index 5460a41..0e464cf 100644
--- a/Packages/AudioPlayer/Runtime/SeSlider.cs
+++ b/Packages/AudioPlayer/Runtime/SeSlider.cs
@@ -4,7 +4,7 @@
 namespace Kameffee.AudioPlayer
 {
     [AddComponentMenu("UI/Audio/SeSlider")]
-    public class SeSlider : MonoBehaviour
+    public sealed class SeSlider : MonoBehaviour
     {
         [SerializeField]
         private Slider seSlider;
diff --git a/Packages/AudioPlayer/Runtime/com.kameffee.audio-player.asmdef b/Packages/AudioPlayer/Runtime/com.kameffee.audio-player.asmdef
index d54f474..6d2c350 100644
--- a/Packages/AudioPlayer/Runtime/com.kameffee.audio-player.asmdef
+++ b/Packages/AudioPlayer/Runtime/com.kameffee.audio-player.asmdef
@@ -1,5 +1,5 @@
 {
-    "name": "AudioManager",
+    "name": "AudioPlayer",
     "references": [],
     "includePlatforms": [],
     "excludePlatforms": [],
diff --git a/Packages/AudioPlayer/package.json b/Packages/AudioPlayer/package.json
index 055fc22..adbea00 100644
--- a/Packages/AudioPlayer/package.json
+++ b/Packages/AudioPlayer/package.json
@@ -1,7 +1,7 @@
 {
   "name": "com.kameffee.audio-player",
   "displayName": "AudioPlayer",
-  "version": "0.0.2",
+  "version": "0.0.3",
   "unity": "2019.4",
   "description": "Simple Audio Player",
   "author": {
@@ -14,8 +14,6 @@
     "bgm"
   ],
   "license": "MIT",
-  "dependencies": {
-  },
   "samples": [
     {
       "displayName": "AudioPlayer Demo",
@@ -23,4 +21,4 @@
       "path": "Samples~/AudioPlayerDemo"
     }
   ]
-}
+}
\ No newline at end of file