... two signal input "+" and "-" First:as counter,can add or minus button or remote control or sensor ... industrial counterhave two signal input “+” and “-“Specification:First:as counter,can add or minus.Second:1, Led high of character ... memory function.Fourth:technical criteria4, Operational environment:temperature -10°C~50°C,relative humidity 0~95%Godrelish Electronic Technology Co., Limited is ...