diff --git a/forge/src/main/java/org/embeddedt/modernfix/forge/mixin/bugfix/unsafe_modded_shape_caches/BackpackShapesMixin.java b/forge/src/main/java/org/embeddedt/modernfix/forge/mixin/bugfix/unsafe_modded_shape_caches/BackpackShapesMixin.java
index 965adf2d..a7f53d71 100644
--- a/forge/src/main/java/org/embeddedt/modernfix/forge/mixin/bugfix/unsafe_modded_shape_caches/BackpackShapesMixin.java
+++ b/forge/src/main/java/org/embeddedt/modernfix/forge/mixin/bugfix/unsafe_modded_shape_caches/BackpackShapesMixin.java
@@ -2,6 +2,7 @@ package org.embeddedt.modernfix.forge.mixin.bugfix.unsafe_modded_shape_caches;
 
 import net.minecraft.world.phys.shapes.VoxelShape;
 import net.p3pp3rf1y.sophisticatedbackpacks.backpack.BackpackShapes;
+import org.embeddedt.modernfix.annotation.RequiresMod;
 import org.spongepowered.asm.mixin.Final;
 import org.spongepowered.asm.mixin.Mixin;
 import org.spongepowered.asm.mixin.Mutable;
@@ -14,6 +15,7 @@ import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 
 @Mixin(value = BackpackShapes.class, remap = false)
+@RequiresMod("sophisticatedbackpacks")
 public abstract class BackpackShapesMixin {
     @Mutable @Shadow @Final private static Map<Integer, VoxelShape> SHAPES;