Aquatec WT221 Classic Whistle. A Classic Whistle that is great for diving, hunting or hiking. If you loose your way, this whistle can be heard for some distance. If you got hurt and need to alert someone it is a life saver! Diving whistle is a great practical accessory for divers and rescue teams! It has the ability to produce loud sounds that can attract attention. Duo-Frequency Whistle. All-Weather Safety Whistle. Volume: 135 dB. Split Ring Attachment. Color: Orange. Material: High Impact ABS with SUS 304 Ring.