Norgren ISI Enclosed Pneumatic Power Wedge Clamp SC63 A 53M 180 R S3 1These clamps are new surplus from General Motors. I have not been able to find a part number break down or any information from Norgren regarding these clamps. I will try to give you a little bit of information based on my observations. The cylinder has a 63mm bore, and a stroke cushion on each end. The ports are 1 4" NPT. It is a standard Norgren air cylinder. The clamp is very similar to norgrens "EC63D" clamps. It uses the same octagonal arm mount