Gold Mountain produced several economy class metal detectors that were not stylish and did not sell that well. Bill Mahn's son, founder of D-Tex bought out Gold Mountain and introduced several new models. One being the VIP, similar to a D-Tex unit. Gold Mountain eventually became Gold Mountain Technologies and introduced several fantastic detectors. These detectors are very much in demand today--GM1650, King Cobra, Thunderstick, Scorpion.
GMT KING COBRA ---- Build your own
A fellow Geotech member KT315 has taken a very popular, in demand, hard to find King Cobra and reproduced a new PCB.
So if your willing to take the challenge you can build your very own version. I ordered two PCB's myself which just arrived.