Is there a function that checks what kind of item you have? (e.g. armor, boots, hat, weapon).
( If not, why don't you add that function with code looking into the otbm file ( or that file that contain the "atk" or "only_wearable_on_weapon_slot" )
( If not, why don't you add that function with code looking into the otbm file ( or that file that contain the "atk" or "only_wearable_on_weapon_slot" )