This is a plastic pivot cap used on Fenestra 1/4 in. top or bottom pivot rods. It is 7/16 in. outside diameter, then expands to a 27/32 in. diameter lip and then reduces down to a 9/32 in. pin on top of that. A unique plastic guide cap that is used by Fenestra and a variety of bi-fold door manufacturers. Plastic Construction Top or Bottom Pivot Cap Fits a 1/4 in. rod Cap is 7/16 in. as it fits onto the guide rod, then expands to a 27/32 in. lip and then reduces down to a 9/32 in. pin on top