diff --git a/flutter_cache_manager_firebase/lib/src/firebase_cache_manager.dart b/flutter_cache_manager_firebase/lib/src/firebase_cache_manager.dart
index e45ed319..72b59e25 100644
--- a/flutter_cache_manager_firebase/lib/src/firebase_cache_manager.dart
+++ b/flutter_cache_manager_firebase/lib/src/firebase_cache_manager.dart
@@ -9,15 +9,15 @@ class FirebaseCacheManager extends CacheManager {
   static const key = 'firebaseCache';
 
   static final FirebaseCacheManager _instance =
-      FirebaseCacheManager._(retryOptions: retryOptions, bucket: bucket);
+      FirebaseCacheManager._(retryOptions: _retryOptions, bucket: _bucket);
 
-  static RetryOptions? retryOptions;
+  static RetryOptions? _retryOptions;
 
-  static String? bucket;
+  static String? _bucket;
 
   factory FirebaseCacheManager({RetryOptions? retryOptions, String? bucket}) {
-    bucket = bucket;
-    retryOptions = retryOptions;
+    _bucket = bucket;
+    _retryOptions = retryOptions;
     return _instance;
   }