Big-Sert 3/8-16 Oversized repair kit includes: Drill, counterbore, tap, tap guide, install driver & high temp sealer (Qty 5) inserts of the .520 length P/n 53811 BIG-SERT OVERSIZED Use after a failed coil style failure. The min depth of  a "BLIND" hole must be at least .770 deep. If you want a kit with a Longer insert .750 reach insert see kit p/n 5381F In a blind hole your min depth should be at least 1.000" inch.