NOTE:The link is the instructions about SainSmart 4-Channel 5V Relay Module. https://s3-ap-northeast-1.amazonaws.com/sain-amzn/20/20-018-101/4+Relay+Module.rar This is a 5V 4-Channel Relay interface board, Be able to control various appliances, and other equipments with large current. It can be controlled directly by Microcontroller(Arduino , 8051, AVR, PIC, DSP, ARM, ARM, MSP430, TTL logic). 5V 4-Channel Relay interface board, and each one needs 15-20mA Driver Current Equiped with high-current relay, AC250V 10A ; DC30V 10A Standard interface that can be controlled directly by microcontroller (Arduino , 8051, AVR, PIC, DSP, ARM, ARM, MSP430, TTL logic) Indication LED"s for Relay output status - 2 pounds