Thread: 5/8"-18Set Includes: (1) Tap, (1) Installation Tool, (6) InsertsDrill Size: 41/64" (Not Included)This Kit Quickly And Permanently Restores Stripped, Worn Or Damaged Threads To Their Original Size And ConditionThe Hard, Stainless Steel (18-8) Diamond Shaped Wire Inserts Work In Just About Any Material; Aluminum, Magnesium, Cast Iron, Bronze, Steel And MoreInserts Have A Driving Tang For Installation Which Is Notched For Easy Removal