ITEM NAME:DC24V 1Channel Optocoupler Driver Relay Module Board Red K3X4 DC24V 1Channel Optocoupler Driver Relay Module Board Red K3X4 Product Name : Relay Module;Model : SRD-24VDC-SL-C Material : Electronic Parts;Number of Channels : 1 Voltage : 24V DC;Load : 10A, AC 250V/125V, DC 30V/28V Size : 5 x 2.6 x 1.8cm/2" x 1" x 0.7"(L*W*H);Color : Red,blue This is 1-Channel, Optocoupler Shielded, high Low level trigger Relay Module. Package : 1 x Relay Module 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 +/-1-3 cm..This is 1-Channel, Optocoupler Shielded, high Low level trigger Relay Module.