No contact, no noise, internal working method, no spark noise generation. The shell is made of transparent high-temperature flame-retardant material, which is glossy, heat-, fire-, and dustproof, sturdy and . Good optocoupler operation for more stable power cycle capability and excellent temperature characteristics. Solid state relays do not have mechanical components and are operated by thyristors to complete contact work. Electroplated aluminum plate has excellent heat dissipation., Weight: 0.77051560569 pounds, Manufacturer: Kueohse