This product is an industrial RS485 interface control 4-way high current relay module, using Modbus RTU protocol, built-in power isolation, magnetic coupling isolation, self-recovery fuse and and other protection circuits, ABS DIN-rail housing design. This product is easy to operate, with fast communication speed, stable, reliable, safe and other characteristics, can be applied to a variety of industrial control equipment or applications with high communication requirements. Colour:Black Material:Aluminum alloy Tips: The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect Use Package Contents: 1 * Relay Modules 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.