I sent a Fisher Gold Bug, Surf Master, 900 Discovery and A Lorenz in for repair. Most 900's sound off with every step but East Texas tuned it perfectly. The Gold bug has some bad potentiometers (tuning controls ) in it, The Surf machine had a broken built in headphone wire. Most of them are 30 years old . I heard about East Texas and shipped my units from central New York. Fair prices and questions answered by John on all of them His info on why two-boxes don't go deep on ammo boxes unless they are on their side for more surface area to be detected got me to switch to the Lorenz. jerefwelch@***.com