Wooster Mini-Koter Professional Roller Frame is designed to work with 6 in. Wooster Mini-Koter Roller Covers. The Wooster Mini-Koter system is great for painting tight areas: behind radiators, pipes or toilet tanks and other narrow spaces where a brush or regular roller won't reach. (Wooster Mini-Koter Roller Frame is compatible with most mini rod-style roller covers.) The handle is threaded for attachment to all extension poles or can clip to Wooster Sherlock GT poles.