5V High/Low Level Trigger Opto-isolator 4-Channel Power Relay Module Product Name : Opto-isolator 4-Channel Power Relay Module;Coil Voltage : DC 5V Working Type : High/Low Level Trigger;Total Size : 43 x 30mm/ 1.7" x 1.2"(L*W) Material : Plastic, Electronic Part Net Weight : 60g Package : 1 x Opto-isolator 4-Channel Power Relay Module