... pressing kinds of concave-convex figures and characters. Equipped with some simple devices, it also can be used for ... Hunting frequency 27.12MHZ, 30.56MHZ, 40.68MHZ, accord with international standard and little jamming to outside equipments. 3. Fireproof ... spark killer device is available with good reliablity and effect. Meanwhile it is equipped with overload current protection device. At ...