Amphenol 62GB Strain Relief J Clamps Backshell. From Amphenol, these clamps are for use with unscreened jacketed cable and are supplied without a grommet. The clamp is compatible with Amphenol 62GB connectors. Available in this range. Stock No. ; 539-7129 539-7129 is a 62GB J Clamp, size 08 Stock No. ; 539-7139 539-7139 is a 62GB J Clamp, size 10 Stock No. ; 539-7141 539-7141 is a 62GB J Clamp, size 12 Stock No. ; 539-7157 539-7157 is a 62GB J Clamp, size 14