Heli-Coil 5/16-18 Coarse Thread Repair Kit. It includes 12 stainless steel inserts, a tap, and an installation tool. This kit is designed to repair damaged or stripped threads in automotive, marine, and industrial applications. The stainless steel inserts are corrosion-resistant and provide a strong, durable repair. The tap is used to create a new thread in the damaged hole, and the installation tool is used to insert the inserts.