This thread repair kit is used to repaire or replace damaged or stripped internal screw threads.The kit has altogether 131 pieces, all made according to professional standard.It has one HSS tap for each size, one HSS drill for each size, 2 insert tools for each size, thread inserts for each size, all come complete in a handy storage case.Delivery includes 5x HSS steel drill,5x HSS steel tap,5x inserting tool,5x tang break, and110x steel threaded inserts in a carry case.