HeliCoil Professional Thread Repair Kit All HeliCoil Thread Repair Kits including the Professional Thread Repair Kits are used for creating stronger internal threads in all metals, composites, polymers and other materials by repairing damaged or stripped internal threads and regaining the original thread size. HeliCoil Thread Repair Kit creates longer lasting durable threads, avoids thread over-sizing, increases the possibility of higher torque application in weaker metals, significantly reduces the bolt breaking problems & HeliCoil being made of stainless steel protects against atmospheric corrosion. HeliCoil Professional Thread Repair Kits include everything required to do the job right good number of inserts each of 3 lengths (short, medium & long) for multiple applications, HSS drill bit ,Finishing tap, installation tool and tang breaking tool ?all in a rugged new box. These kits are available in metric range M2 to M12 and in UNC/UNF range #4-40 to 1/2". HeliCoil Master Thread Repair Kit HeliCoil Master Thread Repair Kit once again contains everything required to do the job right ?good number of inserts of standard length (1.5D) , HSS drill bit ,Finishing tap, installation tool and tang breaking tool ?all in a rugged box. These kits are available in metric range M14 to M20 and in UNC/UNF range 9/16" to 1-1/2" . HeliCoil Thread Repair Kit ?After Market HeliCoil After Market Thread Repair Kits are available in economy packs with all basic tools required to perform a thread repair. Each kit has a finishing tap, installation tool , a good quantity of 1.5D length of inserts , tang breaking pin and complete instructions. These kits are available as ive range in metric M4 to M20 and in UNC/UNF range #8-32 to 1/2".