diff --git a/src/ImageSharp/ColorSpaces/Conversion/Implementation/Rgb/RgbWorkingSpace.cs b/src/ImageSharp/ColorSpaces/Conversion/Implementation/Rgb/RgbWorkingSpace.cs
index 530c01691..e43215614 100644
--- a/src/ImageSharp/ColorSpaces/Conversion/Implementation/Rgb/RgbWorkingSpace.cs
+++ b/src/ImageSharp/ColorSpaces/Conversion/Implementation/Rgb/RgbWorkingSpace.cs
@@ -6,7 +6,7 @@ namespace SixLabors.ImageSharp.ColorSpaces.Conversion.Implementation.RgbColorSap
     /// <summary>
     /// Trivial implementation of <see cref="IRgbWorkingSpace"/>
     /// </summary>
-    internal readonly struct RgbWorkingSpace : IRgbWorkingSpace
+    internal class RgbWorkingSpace : IRgbWorkingSpace
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="RgbWorkingSpace"/> struct.