diff --git a/CHANGELOG.md b/CHANGELOG.md
index 00fe3e9..633de62 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,8 +5,14 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+
 ### Added
  - Added Get and Set extensions to PropertyInfo in SIMPLSHARP to mimic overloads avaliable in NETSTANDARD
+ - Added Collection extensions for setting and adding ranges of items
+
+### Changed
+ - Repeater changed to use configured callbacks instead of a dumb event
+ - Scheduled action callbacks allow a TimeSpan to be returned to delay actions
 
 ## [12.1.0] - 2020-07-14
 ### Added
diff --git a/ICD.Common.Utils/Extensions/CollectionExtensions.cs b/ICD.Common.Utils/Extensions/CollectionExtensions.cs
new file mode 100644
index 0000000..40fe177
--- /dev/null
+++ b/ICD.Common.Utils/Extensions/CollectionExtensions.cs
@@ -0,0 +1,45 @@
+using System;
+using System.Collections.Generic;
+using ICD.Common.Properties;
+
+namespace ICD.Common.Utils.Extensions
+{
+	public static class CollectionExtensions
+	{
+		/// <summary>
+		/// Clears the collection and adds the given range of items.
+		/// </summary>
+		/// <typeparam name="T"></typeparam>
+		/// <param name="extends"></param>
+		/// <param name="range"></param>
+		public static void SetRange<T>([NotNull] this ICollection<T> extends, [NotNull] IEnumerable<T> range)
+		{
+			if (extends == null)
+				throw new ArgumentNullException("extends");
+
+			if (range == null)
+				throw new ArgumentNullException("range");
+
+			extends.Clear();
+			extends.AddRange(range);
+		}
+
+		/// <summary>
+		/// Adds the given range of items to the collection.
+		/// </summary>
+		/// <typeparam name="T"></typeparam>
+		/// <param name="extends"></param>
+		/// <param name="range"></param>
+		public static void AddRange<T>([NotNull] this ICollection<T> extends, [NotNull] IEnumerable<T> range)
+		{
+			if (extends == null)
+				throw new ArgumentNullException("extends");
+
+			if (range == null)
+				throw new ArgumentNullException("range");
+
+			foreach (T item in range)
+				extends.Add(item);
+		}
+	}
+}
diff --git a/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj b/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj
index 368f8c0..14ef513 100644
--- a/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj
+++ b/ICD.Common.Utils/ICD.Common.Utils_SimplSharp.csproj
@@ -109,6 +109,7 @@
     <None Include="CultureInfo.sqlite">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <Compile Include="Extensions\CollectionExtensions.cs" />
     <Compile Include="ObfuscationSettings.cs" />
     <Compile Include="Extensions\BoolExtensions.cs" />
     <Compile Include="Extensions\ByteExtensions.cs" />