Wooster Mini-Koter rollers have a core/bearing system that gives the Mini-Koter a more universal fit with most mini frames. Best-quality roller fabrics offer excellent paint pickup and a very smooth finish. Use with the Wooster Mini-Koter roller frame when painting tight areas, behind radiators, pipes or toilet tanks and other narrow spaces where a brush or regular roller won't reach. Use the 3/8" nap shed-resistant roller cover in all paints and enamels smooth to semi-smooth surfaces.