The is a Spindle Nut Cage which is used on our Dexter Galvanized Axles. You would use this instead of a cotter pin or tang washer to secure your spindle nut on the threads of your axle spindle.
This is used in conjunction with the thinner Spindle Nut, not the Castle Nut style.
This is for 1" Spindles, which is the size spindle for all axles on our website. We specifically sell this as a replacement for the 3,500lb and 2,000lb Dexter Galvanized Axles.