Heli-Coil 5521-6 3/8-16 wire insert repair kit
Check compatibility
Heli-Coil 5521-6 is for coarse 3/8-16 wire repairs. Use the original 16-TPI designation to distinguish it from 5528-6 for 3/8-24.
Questions before ordering
Which Heli-Coil kit handles the fine version?
5528-6 is the 3/8-24 model. Confirm 16 or 24 TPI on the undamaged fastener before ordering.