Color: Silver 1.Fins Increase the heat dissipation area of the circuit board, making it easier to dissipate heat 2.Aluminum material is resistant to oxidation and corrosion, not suitable for acid and alkali environments 3.When using, apply thermal grease evenly between the solid state relay and the heat sink Specification: 1.Model: AI-50W 2.Color: silver 3.Material: Aluminum 4.After-Sales Guarantee: Aracombie has a 24-hour human customer service. If you have any questions before purchasing or are not 100% satisfied with the product, please feel free to contact us, and we will provide you with solutions as soon as possible .