To220 bolt on heat sink trusemi bk t220 0022 02 to220 bolt on heatsink black anodized finish 21 c w thermal resistance 19mm long 19mm wide 9 5mm high black anodised pre drilled heatsink to accept a wide variety of to220 packaged semiconductors i e voltage regulators and power transistors may be mounted horizontally or vertically trusemi bk t220 0022 02 to220 bolt on heat sink