2.7 to 5.5 K/W for TO 220. Available lengths: SK64 37.5 mm and 75 mm SK68 37.5 mm, 50 mm, 75 mm and 100 mm Pitch-free thread (labelled M3) for type SK68 profile pressed and non-standard Matching M3x8 socket head screws with a screw thread of 2.9 to 2.94 mm in accordance with DIN 84