Wooster Jumbo-Koter 50/50 Roller Covers are 50% natural wool and 50% polyester in a high-performance fabric blend. The shed-resistant construction offers improved resistance to matting and spattering, along with excellent paint pickup and release. An affordable alternative to 100% wool. Wooster Jumbo-Koter (Mini Cage) Rollers are smooth-rolling - they do not skid like rod-style mini rollers can. They're great for any area with a lot of fixtures, trim, or windows resulting in small spaces. Additional painting project uses; cabinets, doors, kitchens, baths, closets, and hallways. To be used on the 4-1/2 in. Pro Sherlock Mini Cage Frames. Resealable bag for easy storage.