diff --git a/init.lua b/init.lua
index f5e4f46..6effa5d 100644
--- a/init.lua
+++ b/init.lua
@@ -137,8 +137,8 @@ for material, m in pairs(materials) do
 				["armor_"..p.place] = math.floor(p.level * m.armor),
 				armor_heal = m.heal,
 				armor_use = m.use,
-				armor_radiation = math.floor(p.radlevel * m.radiation)
-			}
+			},
+			armor_groups = { radiation = math.floor(p.radlevel * m.radiation)},
 		})
 		minetest.register_craft({
 			output = name,