Pool Leak Pro Hydrophone HYDROPHONE with AMPLIFIER & SPEAKER For pool leak detection You can hear the smallest of leaks with OVER 20 ft. CABLE. we added velcro straps to mount it to a pool poll for easy searching from out side the pool. with pocket size battary operated amp. With it's own speaker, nice and loud with out the headphones. A NEW BATTERY HAS BEEN INSTALLED JUST BEFOR SHIPPING Also great for Listing to the fascinating world that lies under the sea !Hear whales, dolphins, manatees, seals, fish, shrimp and more. PLUG and PLAY JUST ADD WATER (Battary included ) 2-Year Warranty Just return for repair or replacement