JW Fishers SLFP-1 Low Frequency PingerJW Fishers SLFP 1 Low Frequency Pinger Acoustic pingers are devices that generate acoustic signals underwater. They are used to mark an underwater site or piece of equipment so a returning diver, using a pinger receiver, can locate the exact spot. Pingers are available with different transmit frequencies so several can be deployed in the same general area without interference from each other. The diver adjusts his pinger receiver to the frequency of