diff --git a/src/main/kotlin/moe/nea/firmament/rei/SBItemEntryDefinition.kt b/src/main/kotlin/moe/nea/firmament/rei/SBItemEntryDefinition.kt
index 3ad27e2..780fd78 100644
--- a/src/main/kotlin/moe/nea/firmament/rei/SBItemEntryDefinition.kt
+++ b/src/main/kotlin/moe/nea/firmament/rei/SBItemEntryDefinition.kt
@@ -66,7 +66,7 @@ data class SBItemStack(
 
     fun getStackSize() = stackSize
     fun setStackSize(newSize: Int) {
-        this.stackSize = stackSize
+        this.stackSize = newSize
         this.itemStack_ = null
     }