Vintage copper heatsink for SO-2 transistors. or any 5.5 to 6mm diameter transistor. Dims: height : 15.5mm, depth to flange 12.5mm, flange: 10mm, flange slot : 3.4mm across. This neat design also allows for bolting to a backplate or larger heatsink. Status: NOS (New Old Stock) One for the vintage radio restorers ! RoHS compliant: no