Frames have exclusive, easy-roll cage Like high-quality standard frames, the roller moves freely and wont slide up the wall Frame accepts both 4-1/2 (3651-2077) and 6-1/2 (3651-2101) rollers-choose from two different lengths Because of unique system, Jumbo-Koter rollers only work with Wooster Jumbo-Koter frames Solvent-resistant plastic cage, extra-smooth rolling action Chrome-plated 1/4 shank Professional polypropylene grip with reinforced threads, Sherlock GT compatible 14 length