Chuck, Collet Type Nelson Style Collet, For Maximum Stud Length 2 1/2 in, For Stud Diameter 0.138 in, Stud Welding Process Capacitive Discharge, For Welder Series NCD, NCD+, Overall Diameter 3/8 in, Overall Length 2 3/8 in, Welding Processes Stud Welding, Thread Size #6 -32, For Minimum Stud Length 1/4 in, For Use With Nelson CD stud welding equipment, Nelson style stop pins, Material Copper Alloy