To begin installation, the helical coil is inserted into the pre-drilled hole. To screw the helical insert into the hole, you will need a means to secure the coil so it will rotate for proper installation. This is where you have to decide between tanged or tang-free coils. 

A tanged helical insert extends the end of the coil wire across the radius of the coil. This provides a grip point for the helical insert tool so it can rotate the coil insert to snugly fit in the hole. After the coil is inserted, the tang must be removed before you can screw in the fastener or bolt.

A tang-free helical insert is installed in much the same way, although instead of using a metal coil tang that has to be removed after installation, tang-free inserts have a drive notch in the helical coil that is used as a grip point for the helical insert tools.