The HardCORE Carriage Cap allows you to use SHUT IT’s carriage plates on a round bottom rail. The "adapter” is 
perfect for chainlink gates and creates same UL325- friendly system that the HardCORE Carriage Caps do with ornamental gates. Designed to be used with the CI2420 4" (102mm) and CI2620 6" (152mm) HardCORE V-Groove Wheels. Carriage Plates replace traditional wheel boxes and enable you to install the HardCORE Gate Wheel inside the bottom rail of the gate itself