XS Scuba - Wind Storm™ Safety Whistle TUSA Add Duo Air 2 The design of the nose

The design of the nose pocket makes it easy to equalize while descending

Available in 3 mm and 5 mm thicknesses

Each 1st stage has three medium pressure ports and one high pressure port

This provides two benefits:

System of Measurement Metric - Imperial

XS Scuba - Wind Storm™ Safety Whistle TUSA Add Duo Air 2 The design of the noseThe Wind Storm whistles outperform all of the other leading brands of whistles. It even works underwater, up to 50 ft (15. 25 m). Performs in all conditions, in any weather Can be heard on land up to 1 2 mile (804 m) away! Can be heard underwater for a distance of up to 50 ft (15. 25 m)! SOLAS Coast Guard approved