Short Description: Making noise under water doesnt get any simpler than this. Marketing Product Type - Accessories X-Tek, Other Product Weight 0.1 lb Activity Recreational UPC 4048336345903 Elastic band, made of surgical tubing, is fitted with a hard plastic ball. Stretch the band over your scuba tank. To get your buddys attention, reach back, grab hold of the ball, pull it away from the tank, and let it go. The clang is sure to turn heads.