Onboard high-performance micro-controller chips. Onboard CH340 USB control chip. Onboard LED power lights and relay status LED lights. Onboard 5 v,10 A / 250 VAC,10 A / 30 VDC relays,relay's long life can absorb 100000 times in a row. Module with over-current protection and relay diode current protection function. Colour:blue Material:metal PCB size: 49.6 (mm) x16 (mm) USB switch the default communication baud rate: 9600 BPS USB switch communication protocol Data (1) - startup logo (the default is 0 xA0) Data (2) - switch address code (the default is 0 x01, identifies the first switch) Data (3) - operation data (0 x00 to "off", 0 x01 to "on") Data (4) - check code Package Included: 4 x LCUS - type 1 USB relay module USB intelligent switch control 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.