metal whistle with opener logo engrave .zinc metal material/ factory direct supply metal whistleWe professionally supply various whistles especially metal whistles as follows:1. material: iron,copper,aluminium alloy and plastic.2. size: optional3. pattern: 6-shape,1-shape,bullet-shape,rocket-shape and football-shape,etc.4. colour: as per pantone5. LOGO: Customized6. accessories: key ring,lanyards ...