The Scuba Rattle Stick is a fantastic tool. For those that dont know what a Scuba Rattle Stick is, it is a short stick made of a corrosive-resistant metal, with a clip at one-end which a lanyard can be attached, and a rattle on the other end. The XS Scuba Rattle Stick with Clip can be used as a signal device, by shaking it to get your buddies attention. The sound it makes is nice and loud underwater for easy identification of the noise source. The Rattle Stick is a great tool for dive masters or guides that wish to get their groups attention. Need to run silent, XS Scubas Rattle Stick has a cap with magnetic to prevent unwanted sounds. Rattle Stick with Clip measures (L x D) 5.5" x 1" (14 x 2.5 cm).