Based on for Raspberry Pi 40pin GPIO interface, suitable for Raspberry Pi series motherboards Use high-quality relays to allow access to loads: less than equal 5A 250V AC or less than equal 5A 30V DC With optocoupler isolation to avoid interference from high-voltage circuits With relay indicator light, it is convenient to check the working status of the relay With relay selection jumper cap, it is convenient to switch other pins of for Raspberry Pi for control Provide complete supporting information manual (including wiringPi, WebioPi, shell, python and bcm2835 routines) Due to different batches, the appearance, color and printed words of the product may vary, which will not affect the use. Colour:Blue Material:PCB Size:65.15 x 56.21mm Package Contents: 1 * Relay Extention Board Only the above package content, other products are not included. Note: Light reflection 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.