An extruded black anodised aluminium heatsink, with two plated steel locating pegs. - 2.6 mm diameter at 25.4 mm centres (same channel can be used for the insertion of self tapping srews ! ) 38 mm high ( excluding pegs) x 35 mm wide x 12.73mm deep. Undrilled, thus allowing for a range of differing semiconductor types apart from TO-220 / 218 / 247's Thermal resistance 10 degrees per Watt. weight 17g