diff --git a/README.md b/README.md
index 712f02e..5bf0a21 100644
--- a/README.md
+++ b/README.md
@@ -80,11 +80,13 @@ public void ConfigureServices(IServiceCollection services)
 
         // limit the total entries in the MemoryCache
         //   each unique user agent string counts as one entry
-        options.CacheOptions.SizeLimit = 1024; // default is 256
+        options.CacheOptions.SizeLimit = 1024; // default is null (= no limit)
     });
 }
 ```
 
+> `AddHttpUserAgentMemoryCachedParser` registers `HttpUserAgentParserMemoryCachedProvider` as singleton which contains an isolated `MemoryCache` object.
+
 ### ASP.NET Core
 
 For ASP.NET Core applications, an accessor pattern (`IHttpUserAgentParserAccessor`) implementation can be registered additionally that independently retrieves the user agent based on the `HttpContextAccessor`. This requires the package [MyCSharp.HttpUserAgentParser.AspNetCore](https://www.nuget.org/packages/MyCSharp.HttpUserAgentParser.AspNetCore)
diff --git a/src/MyCSharp.HttpUserAgentParser.MemoryCache/HttpUserAgentParserMemoryCachedProvider.cs b/src/MyCSharp.HttpUserAgentParser.MemoryCache/HttpUserAgentParserMemoryCachedProvider.cs
index a8f8f1d..9ff4fda 100644
--- a/src/MyCSharp.HttpUserAgentParser.MemoryCache/HttpUserAgentParserMemoryCachedProvider.cs
+++ b/src/MyCSharp.HttpUserAgentParser.MemoryCache/HttpUserAgentParserMemoryCachedProvider.cs
@@ -15,11 +15,10 @@ public class HttpUserAgentParserMemoryCachedProvider : IHttpUserAgentParserProvi
         /// <summary>
         /// Creates a new instance of <see cref="HttpUserAgentParserMemoryCachedProvider"/>.
         /// </summary>
-        /// <param name="memoryCache">The memory cache instance to use</param>
         /// <param name="options">The options used to set expiration and size limit</param>
-        public HttpUserAgentParserMemoryCachedProvider(IMemoryCache memoryCache, HttpUserAgentParserMemoryCachedProviderOptions options)
+        public HttpUserAgentParserMemoryCachedProvider(HttpUserAgentParserMemoryCachedProviderOptions options)
         {
-            _memoryCache = memoryCache;
+            _memoryCache = new Microsoft.Extensions.Caching.Memory.MemoryCache(options.CacheOptions);
             _options = options;
         }
 
diff --git a/src/MyCSharp.HttpUserAgentParser.MemoryCache/HttpUserAgentParserMemoryCachedProviderOptions.cs b/src/MyCSharp.HttpUserAgentParser.MemoryCache/HttpUserAgentParserMemoryCachedProviderOptions.cs
index 6299576..3bf5aaa 100644
--- a/src/MyCSharp.HttpUserAgentParser.MemoryCache/HttpUserAgentParserMemoryCachedProviderOptions.cs
+++ b/src/MyCSharp.HttpUserAgentParser.MemoryCache/HttpUserAgentParserMemoryCachedProviderOptions.cs
@@ -8,7 +8,6 @@ namespace MyCSharp.HttpUserAgentParser.MemoryCache
     /// <summary>
     /// Provider options for <see cref="HttpUserAgentParserMemoryCachedProvider"/>
     /// <remarks>
-    /// Default of <seealso cref="MemoryCacheOptions.SizeLimit"/> is 256.
     /// Default of <seealso cref="MemoryCacheEntryOptions.SlidingExpiration"/> is 1 day
     /// </remarks>
     /// </summary>
@@ -46,11 +45,7 @@ public HttpUserAgentParserMemoryCachedProviderOptions(MemoryCacheOptions? cacheO
                 // defaults
                 SlidingExpiration = TimeSpan.FromDays(1)
             };
-            this.CacheOptions = cacheOptions ?? new MemoryCacheOptions
-            {
-                // defaults
-                SizeLimit = 256
-            };
+            this.CacheOptions = cacheOptions ?? new MemoryCacheOptions();
         }
     }
 }
diff --git a/tests/MyCSharp.HttpUserAgentParser.MemoryCache.UnitTests/HttpUserAgentParserMemoryCachedProviderTests.cs b/tests/MyCSharp.HttpUserAgentParser.MemoryCache.UnitTests/HttpUserAgentParserMemoryCachedProviderTests.cs
index 53d5c58..8f461b6 100644
--- a/tests/MyCSharp.HttpUserAgentParser.MemoryCache.UnitTests/HttpUserAgentParserMemoryCachedProviderTests.cs
+++ b/tests/MyCSharp.HttpUserAgentParser.MemoryCache.UnitTests/HttpUserAgentParserMemoryCachedProviderTests.cs
@@ -1,7 +1,6 @@
 // Copyright © myCSharp 2020-2021, all rights reserved
 
 using FluentAssertions;
-using Microsoft.Extensions.Caching.Memory;
 using Xunit;
 
 namespace MyCSharp.HttpUserAgentParser.MemoryCache.UnitTests
@@ -12,9 +11,8 @@ public class HttpUserAgentParserMemoryCachedProviderTests
         public void Parse()
         {
             HttpUserAgentParserMemoryCachedProviderOptions cachedProviderOptions = new();
-            IMemoryCache memoryCache = new Microsoft.Extensions.Caching.Memory.MemoryCache(cachedProviderOptions.CacheOptions);
 
-            HttpUserAgentParserMemoryCachedProvider provider = new(memoryCache, cachedProviderOptions);
+            HttpUserAgentParserMemoryCachedProvider provider = new(cachedProviderOptions);
 
             // create first
             string userAgentOne =