We developed the BFD SP for those who asked for a quick and easy storage solution for the new and improved BFD Tube when it was not in use. The BFD SP can affix to A PROPERLY SIZED Picatinny rail and some that are misshapen too, like the cheapo imported stuff. The BFD SP can be used as a handstop with or without a BFD Thread Protector in place on the SP, as a vertical fore-grip with the BFD tube affixed (We recommend paying attention to or learning of any potentially applicable laws that may affect your freedom if you run a Vertical Fore Grip on your rifle) or just a place to keep your BFD Tube when it's not covering your brake. Questions? Email sales@icdproducts.com