10 pieces 9mm x 9mm x 4mm VRM copper heatsink include pre applied heat conductive double side adhesive tape for optimum heat transfer. These heat sinks have profiles which are short enough to fit within cases. These heat sinks kit can be applied to cool VRM Stepper Driver MOSFET Regulators Laptop PC etc. Main Body Material: Copper. Thermal conductivity: 401W/mK. Package includes 10 pieces copper heat sinks: 0.35 x 0.35 x 0.16 inch / 9mm x 9mm x 4mm (L*W*H)