A distorted thread grips the screw to resist loosening. Without a prong to break off and retrieve, these inserts are often used where debris could cause damage. Also known as Heli-Coil inserts, they have coils that expand once installed to securely anchor the insert. Installation requires a drill bit, a helical insert tap, and an installation tool.

Inserts that meet DIN 8140 adhere to international standards for dimensions.

For technical drawings and 3-D models, click on a part number.