Integral Stack Lock The world's only keyed, locking device to secure and lock full Packout organizer stacks. Secures any Packout with side rails.  Unistrut Design: We intentionally built this system to be compatible with Unistrut. Unistrut is not included and must be purchased separately. 1-5/8" width Unistrut is required with a minimum length of 26.25". Any depth is okay. 26.25" of Unistrut length is required per locking kit. Comes with track nuts to attach the locks to the Unistrut.  Secure & Lock Stacks: Includes both sides of the locking device, unistrut track nuts, and all hardware. This is perfect for outfitting a full wall in a trailer, van, etc. Larger sections of unistrut can be purchased separately to attach this mechanism.  When locked, Packout organizers are fully secured and can't be removed. Spring-loaded system accepts any Packout organizer with rails. Attach and detach within seconds.  Universal applications are also possible. Bolt the lock system to Unistrut or any other generic rail system. Bolt to any flat, level surface.  Features Anodized aluminum parts. Rust-resistant, coated stainless lock with a silicon boot to seal from moisture.  All hardware is included (Unistrut not included) Fitment  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. Installation instructions can be seen here. Patent Pending  Utility patent pending.