1.5kg striking weight.Automatically grips stud welding nails. Spring release.Suitable for use with 2 & 2.5mm stud nails, please see Power-TEC Part Nos. 91830 & 91831.Ideal for use with Power-TEC Tec-Spot Welders, Part Nos. 91975 & 92314.Replacement jaws available, Part No. 91017.