* Heli-Coil inserts are packaged according to thread size for easy handling and display. * The inserts are contained in a sturdy clear plastic display box and marked with part number and * Measures: M10 x 1.5 x 15.0. * The length of the inserts in inch and metric packages is 1 1/2 times the diameter of the bolt. This * Spark plug hole inserts are packaged in lengths corresponding to the various spark plug reaches.