diff --git a/src/EcsFilter.cs b/src/EcsFilter.cs
index 5056930..13beba7 100644
--- a/src/EcsFilter.cs
+++ b/src/EcsFilter.cs
@@ -7,7 +7,7 @@ namespace DCFApixels.DragonECS
         #region Properties
         public IEcsWorld World { get; }
         public EcsMask Mask { get; }
-        public IEcsReadonlyGroup Entities { get; }
+        public EcsReadonlyGroup Entities { get; }
         public int EntitiesCount { get; }
         #endregion
     }
@@ -29,10 +29,10 @@ namespace DCFApixels.DragonECS
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get => _mask;
         }
-        public IEcsReadonlyGroup Entities
+        public EcsReadonlyGroup Entities
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
-            get => _entities;
+            get => _entities.Readonly;
         }
         public int EntitiesCount
         {
diff --git a/src/EcsGroup.cs b/src/EcsGroup.cs
index 40576a6..d6353f1 100644
--- a/src/EcsGroup.cs
+++ b/src/EcsGroup.cs
@@ -1,26 +1,33 @@
 using System;
 using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
 using delayedOp = System.Int32;
 
 namespace DCFApixels.DragonECS
 {
-    public interface IEcsReadonlyGroup
+    [StructLayout(LayoutKind.Sequential, Pack = 0, Size = 8)]
+    public readonly ref struct EcsReadonlyGroup
     {
-        int Count { get; }
-        bool Contains(int entityID);
-        EcsGroup.Enumerator GetEnumerator();
-    }
-    public interface IEcsGroup : IEcsReadonlyGroup
-    {
-        void Add(int entityID);
-        void Remove(int entityID);
+        private readonly EcsGroup _source;
+
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public EcsReadonlyGroup(EcsGroup source) => _source = source;
+        public int Count
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get => _source.Count;
+        }
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public bool Contains(int entityID) => _source.Contains(entityID);
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public EcsGroup.Enumerator GetEnumerator() => _source.GetEnumerator();
     }
 
     // не может содержать значение 0
     // _delayedOps это int[] для отложенных операций, хранятся отложенные операции в виде int значения, если старший бит = 0 то это опреация добавленияб если = 1 то это операция вычитания
 
     // this collection can only store numbers greater than 0
-    public class EcsGroup : IEcsGroup  
+    public class EcsGroup  
     {
         public const int DEALAYED_ADD = 0;
         public const int DEALAYED_REMOVE = int.MinValue;
@@ -44,6 +51,11 @@ namespace DCFApixels.DragonECS
             [MethodImpl(MethodImplOptions.AggressiveInlining)]
             get => _count;
         }
+        public EcsReadonlyGroup Readonly
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]
+            get => new EcsReadonlyGroup(this);
+        }
         #endregion
 
         #region Constrcutors
@@ -86,7 +98,7 @@ namespace DCFApixels.DragonECS
             if(++_count >= _dense.Length) 
                 Array.Resize(ref _dense, _dense.Length << 1);
 
-            if (entityID > _sparse.Length)
+            if (entityID >= _sparse.Length)
             {
                 int neadedSpace = _sparse.Length;
                 while (entityID >= neadedSpace) 
@@ -128,20 +140,21 @@ namespace DCFApixels.DragonECS
         //TODO добавить автосоритровку при каждом GetEnumerator
 
         #region AddGroup/RemoveGroup
-        public void AddGroup(IEcsReadonlyGroup group)
+        public void AddGroup(EcsReadonlyGroup group)
         {
-            foreach (var item in group)
-            {
-                Add(item.id);
-            }
+            foreach (var item in group) Add(item.id);
         }
-
-        public void RemoveGroup(IEcsReadonlyGroup group)
+        public void RemoveGroup(EcsReadonlyGroup group)
         {
-            foreach (var item in group)
-            {
-                Remove(item.id);
-            }
+            foreach (var item in group) Remove(item.id);
+        }
+        public void AddGroup(EcsGroup group)
+        {
+            foreach (var item in group) Add(item.id);
+        }
+        public void RemoveGroup(EcsGroup group)
+        {
+            foreach (var item in group) Remove(item.id);
         }
         #endregion
 
@@ -179,7 +192,7 @@ namespace DCFApixels.DragonECS
         }
         #endregion
 
-        #region Utils
+        #region Enumerator
         public struct Enumerator : IDisposable
         {
             private readonly EcsGroup _source;
diff --git a/src/EcsPool.cs b/src/EcsPool.cs
index ceba905..e25c161 100644
--- a/src/EcsPool.cs
+++ b/src/EcsPool.cs
@@ -6,7 +6,11 @@ namespace DCFApixels.DragonECS
 {
     public interface IEcsPool
     {
+        public int EntitiesCount { get; }
+        public int Capacity { get; }
+
         public IEcsWorld World { get; }
+        public Type DataType { get; }
         public int ID { get; }
         public bool Has(int index);
         public void Write(int index);
@@ -30,7 +34,12 @@ namespace DCFApixels.DragonECS
         }
 
         public IEcsWorld World => _source;
+        public Type DataType => typeof(void);
         public int ID => -1;
+
+        public int EntitiesCount => 0;
+        public int Capacity => 1;
+
         public void Del(int index) { }
         public bool Has(int index) => false;
         public void Write(int index) { }
@@ -47,7 +56,11 @@ namespace DCFApixels.DragonECS
         private IEcsComponentReset<T> _componentResetHandler;
 
         #region Properites
+        public int EntitiesCount => _sparseSet.Count;
+        public int Capacity => _sparseSet.CapacityDense;
+
         public IEcsWorld World => _source;
+        public Type DataType => typeof(T);
         public int ID => _id;
         #endregion
 
@@ -112,6 +125,7 @@ namespace DCFApixels.DragonECS
         #endregion
     }
 
+    #region ComponentResetHandler
     internal static class ComponentResetHandler
     {
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -137,4 +151,5 @@ namespace DCFApixels.DragonECS
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         public void Reset(ref T component) => _fakeInstnace.Reset(ref component);
     }
+    #endregion
 }
diff --git a/src/EcsWorld.cs b/src/EcsWorld.cs
index 6c05a43..5c29815 100644
--- a/src/EcsWorld.cs
+++ b/src/EcsWorld.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Runtime.CompilerServices;
 
 namespace DCFApixels.DragonECS
@@ -13,6 +14,12 @@ namespace DCFApixels.DragonECS
         public int ID { get; }
         #endregion
 
+
+        #region GetterMethods
+        public ReadOnlySpan<IEcsPool> GetAllPools();
+
+        #endregion
+
         #region Methods
         public EcsPool<T> GetPool<T>() where T : struct;
         public EcsFilter Filter<TInc>() where TInc : struct, IInc;
@@ -68,6 +75,11 @@ namespace DCFApixels.DragonECS
 
         private EcsFilter[] _filters;
 
+        #region GetterMethods
+        public ReadOnlySpan<IEcsPool> GetAllPools() => new ReadOnlySpan<IEcsPool>(_pools);
+
+        #endregion
+
         #region Properties
         public bool IsEmpty => _entities.Count < 0;
         public Type ArchetypeType => typeof(TArchetype);