Nitecore NWS10 is the loudest emergency whistle on the market. You can effortlessly produce 120 decibel sound. Made of titanium alloy, NWS10 is durable, lightweight, and compact. You can put it on your keychain or hang it around the neck. Ideal for boating, scuba diving, hikers, and personal safety. Widely used by Security, Military, Police, and crime prevention units.