No contact, no noise, internal working , no spark noise generation Good optocoupler operation for more stable power cycle capability and excellent temperature characteristics The shell is made of transparent high-temperature flame-retardant material, which is glossy, heat-resistant, fire-resistant, and dustproof, sturdy and . Solid state relays do not have mechanical components and are operated by thyristors to complete contact work Electroplated aluminum plate has excellent heat dissipation Due to different batches, there may be differences in product appearance and printed text, which will not affect use Colour:Black Material:ABS type:25A Package Contents: 1 x Solid State Relay 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.