Back Stop Lock Nut is a lightweight guarantee that your reel will stay put no matter what the conditions.
Unlike "jam" nuts that simply bind one set of threads against another to create a "lock", Back Stop is a unique double-nut system with a floating collar between the nuts that locks down the position of the reel seat hood without tightening the hood further against the reel foot. This unique "floating collar" actually tightens when the hood nut attempts to loosen, and generates a pushing force against the hood nut. Completely eliminates reel foot loosening. Available in extended nut (LOS16/AN) or a hidden thread collar (LOK16/AN) similar to the KDPS hood.
Nice all plastic and will work for locking reel down if there is no for grip so it can unscrew above the threads to put reel on but taller than expected. Looking for a thinner nut made of aluminum.