Bisco Tool Supply carries metric and fractional threaded insert kits / thread repair kits. We have hard to find inserts kits as well. All of our kits come with inserts, tap, and installation tool. Drill bits must be purchased separately. Repair stripped or damaged threads in any metal. Can also be used in new die castings and plastics. Precision inserts are helical coils of 18-8 stainless steel wire. Affordable alternative to Helicoil brand.