Mountain alloy whistle by Lifesystems is manufactured from tough lightweight aluminium alloy, & is recommended as an essential piece of kit for people in the outdoors. This whistle has an anodised body with a keyring attachment & a single blast can reach 100 decibels. A whistle can be used to alert people if you are in distress. The internationally recognised distress signal is 6 blasts of the whistle with a 1 minute break & then repeated. The reply is 3 blasts with the same pause.