@@ChanvibolPen its just backwards way round mate, just unscrew coil bolt and take it out then spin the coil the other way. Detector balance will be lots better.
These are Chinese copies of the Techtronix G2 they're available from Amazon at around £200 and they're good value for money quite robust and get excellent reviews
Thanks you. I bought it from aliexpress app.It's made in China. It is detect all metal and the number show detect along by by area or ground allergy with metal,such as wet,dry,normal or metal change in the ground. Such as fe or iron's munber=20...35. Aluminuim=40....58, Coper or Cu=70...85.gold=90 or 58.., and some metal mix togeter like coper aluminium fe and it's number is 70...81.. in the ground or sand.