diff --git a/lib.lua b/lib.lua
index 07e47dd..27d5b04 100644
--- a/lib.lua
+++ b/lib.lua
@@ -170,9 +170,9 @@ end
 
 -- Gets the internal identifier of an item - unique (hopefully) per type of item, as defined by NBT, metadata/damage and ID/name
 local function get_internal_identifier(item)
-    local n = item.name
-    if item.damage then n = n .. ":" .. item.damage end
-    if item.nbtHash then n = n .. "#" .. item.nbtHash end
+    local n = item.ID
+    if item.meta then n = n .. ":" .. item.meta end
+    if item.NBT_hash then n = n .. "#" .. item.NBT_hash end
     return n
 end