Functions and Features ①Full-auto two-way intercom ②Fine circuit thoroughly, avoid echo and squeal problem. ③Substation is thin and compact, and appearance is handsome ④voice is lifelike, clear, the volume of master station and substation can be adjusted separately. ⑤Easy Installation, only one wire for connecting master station and substation ⑥With recorder jack, can connect record external equipment Specification Working Voltage:DC12V Working Current:300mA Working Environment term: -10℃~60℃ Master Station Size:122*105*38mm Substation Size:65*20mm Packing: printed/white box Box size: 98*58*30mm G.W. 0.8kg; N.W. 0.7kg Outer packing: carton Carton size: 50*31*43cm; 20pcs/ctn G.W:16kg N.W: 14kg Carton size: 50*45*43cm; 30pcs/ctn G.W:24kg N.W: 21kg