metal whistle with opener logo engrave .zinc metal material/ factory ... especially metal whistles as follows:1. material: iron,copper,aluminium alloy and plastic.2. size: optional3. pattern: 6-shape, ... metal whistles as follows:1. material: iron,copper,aluminium alloy and plastic.2. size: optional3. pattern: 6-shape, ... packing: each packing or as your request. metal whistle with opener function