Although they work well on any automotive steel requiring stud welding as part of the repair, this unique design allows for superior welding on the newer high strength lightweight steel, common in today's collision repair market. The new tip design allows for a stronger and easier weld process. The 1001 Flexpert Welding Studs are the most popular stud sold. They are 2.2 mm, copper coated and have been specially designed for easy welding and easy removal after the pulling is complete. The shafts are strong yet flexible. This is the preferred stud for use with slide hammers.