This design is a narrow rail type, mainly for installation in a small space, and comes with a radiator, no need to buy an additional radiator, which satisfies the customer's installation problems to a certain extent. Solid state relays (screw terminal connection) have high strength, shock resistance, strong vibration resistance, and low requirements for input current. They can be easily connected with the digital control circuit of the computer. . It is a replacement product of AC and DC contactors. They are designed for harsh environments with corrosion, moisture or light/explosion protection requirements and frequent power on and off requirements.