Fisher CZ-21 Quick Silver

The Fisher CZ-21 Quick Silver is a fully submersible detector designed above all for water hunting, from the dry sand to deep SCUBA dives. Its housing is leak-proof to 250 feet, and its patented dual-frequency system runs 5 kHz and 15 kHz together, using Fourier domain signal analysis to stay stable in salt water and wet sand. It is one of the few VLF detectors built to work reliably both underwater and on dry land.

In discrimination mode a three-tone audio target ID tells you what you have found without looking at a screen, which is ideal underwater. There is an all-metal auto-tune mode, push-button no-motion pinpointing, manual ground balance for salt or fresh water, a large-target alert and a faint-target boost to help catch weaker signals. These features make it practical for both beginners and experienced underwater hunters.

Power comes from four 9V batteries for around 45 hours. The pole collapses, and the control box can be mounted on the shaft, hip or chest. Supplied with hardwired submersible headphones and a hard-wired 8-inch or 10.5-inch concentric coil, it suits Pakistani divers and beach hunters along the Karachi coast and other salt-water sites. It is a long-standing favourite among divers who hunt for lost rings and old coins.