These patent pending Hazard 4(R) exclusive add-on's to our shell packs allow for the rock solid mounting of hardware and loads thereby expanding the usability of the pack shell greatly. They screw into the top and bottom HardPoint(R) grommets (screws and backers not included) and will allow the strapping down of helmets, skateboards, firearms, jackets, etc. between them using our optional bungee cords, 1" straps, paracord, etc. This is done by the variety of thoughtful slots and holes molded into the tough nylon construction. The slots are also designed to work with popular holster screw systems for the attaching of various index, nylon and leather holsters for knives, machetes, axes, radios, magazines, etc. The various holes and slots can accommodate photographic 1/4 20" screws to mount action cameras, articulating arms, lights, external battery packs, etc. And the relief groove on the back means that the screws or nuts will not stick out the bottom or catch on anything. Use our separately sold HardPoint(R) Screw & Nut Set and HardPoint(R) Stop Gap to screw into hard point system holes (requires 8 screws & 4 backers).