diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/container/IMatteryContainer.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/container/IMatteryContainer.kt
index 7010e7038..16d8b0ff2 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/container/IMatteryContainer.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/container/IMatteryContainer.kt
@@ -225,7 +225,7 @@ interface IMatteryContainer : IContainer, RecipeInput, Iterable<ItemStack> {
 		val list = ArrayList<ItemStack>(size())
 
 		for (i in 0 until size()) {
-			list[i] = this[i]
+			list.add(this[i])
 		}
 
 		return list