Hi-lok head pins are used in conjunction with hi-lok collars to form a secure joint through the use of a the 2 threaded pieces. Designed for specific applications the new threaded hi-lok systems are easier to install and maintain with less special tooling needed. Monroe Aerospace is a stocking distributor of Aerospace and Mil-Spec hardware. We have an extensive inventory of hi-loks. Every part that we sell is in Factory new (FN) condition and we provide our company’s certificate of conformance for all parts on every order. See below for our products.