The Click-Loc™ is the only completely retrofittable locking feature for fluid fittings. The retrofit kit version typically consists of thin wall sleeves that fit over the present male coupling and nut. Retention is by snap fit and the kit can be installed by hand. By using this novel retrofit kit design a fluid fitting which is presently lockwired can be changed to a self locking fitting, usually without changing anything else! No change to the male fitting. No change to the nut. No change to the higher assemblies.
The Click-Loc™ retrofit kit is made of Inconel 718. It can be applied over fittings made of virtually any material including aluminum. Standard wrenches are still used, generally 1/16 inch larger than before. A retrofit kit (shown) was developed to fix a persistent problem of breaking lockwire on flight safety critical fuel line connections on the F-16 and other aircraft. In addition to improving reliability by eliminating the broken wire problem, the customer achieved significant cost savings because much less time was required for fuel nozzle and manifold change-out. This retrofit program is explained in more detail in this USAF TechTip article.