This relay module is 5V active low. Relay output maximum contact is AC250V 10A and DC30V 10A.Standard interface can be directly connected with microcontrollers. This kit is compatible for Arduino IDE, Raspberry Pi and STM32Working status indicator lights are conducive for the safety use4-channel relay interface board, which can be controlled directly by a wide range of microcontrollers such as AVR, PIC, ARM, PLC, etc. It is also able to control various appliances and other equipments with large current.Widely used for all MCU control, industrial sector, PLC control, smart home control.Colour:blueMaterial: PCBSize: 76 x 56mm Package Contents:1x Relay ModuleOnly the above package content, other products are not included.Note: Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.