Aquatec WT230 Flat Fin Shaped Whistle. Loud fin shaped whistle with attachment ring. Diving whistle is a great practical accessory for divers and rescue teams! It has the ability to produce loud sounds that can attract attention. Fin Shaped Whistle. Duo-Frequency Whistle. All-Weather Safety Whistle. Volume: 135 dB. Split Ring Attachment. Color: Orange. Material: High Impact ABS with SUS 304 Ring.