cop whistle metal material standard size loudy sound high-quality Cop whistle:1 item name: Cop whistle2 material: iron or copper3 size: length: 48MM, width: 18MM4 accessory: metal ring,metal chain,lanyard,etc5 packing: in a opp bag or transparent plastic box6 function: police whistle,army whistle7 MOQ: 2000 pcs8 lead time: depends on order quantity metal cop whistle