The Integral Stack Lock is a purpose-built keyed locking system designed to secure full Milwaukee Packout organizer stacks. It locks and stabilizes any Packout organizer with aluminum side rails to help keep your stack securely in place. The system is designed to work with standard 1-5/8-inch Unistrut. Unistrut is not included and must be purchased separately. Each locking kit requires a minimum Unistrut length of 26.25 inches, while any Unistrut depth can be used. Track nuts are included to attach the locks to the Unistrut. Each kit includes both sides of the locking device, Unistrut track nuts, and all required hardware. It's ideal for outfitting a full wall in a trailer, van, or similar application. If you need a longer installation, larger sections of Unistrut can be purchased separately. Once locked, Packout organizers are secured and cannot be removed. The spring-loaded design accepts any Packout organizer with side rails and allows organizers to be attached or removed in just seconds. The Stack Lock can also be used in universal applications. It can be bolted to Unistrut, other compatible rail systems, or any flat, level surface. Fitment Notes: Fits and locks all full-size Milwaukee Packout organizers with aluminum rails on the sides. The included track nuts work with standard, 1-5/8" Unistrut. It could be mounted universally to various flat, level surfaces or other rail systems.