... with certificate, coal mine used ,best quality1.AplicationKTH106-Z mining explosion-proof intrinsically safe automatic telephone is produced according to the standard ... , configured with KTA104 mining telephone coupler and dispatching desk whose outputting signal meets requirement or switch, to achieve safe ... 1dB4)dimension 5)weight:4.4KGS POPULAR!!! BOZZ Mining Explosion-proof Automatic Telephone