The 4" width is a mini-plus roller cover -- cabinet fronts, shelves, small doors, and confined areas where the 3" is too small and the 9" is too big. The Poly-Roller by Jen is a throw-away roller cover made from the same specially patented urethane foam as Jen's Poly-Brush, and lays down thin, even coats with less spatter than a nap roller.

• Made from Jen's specially patented polyurethane foam, the same material as the Poly-Brush
• Ideal for the application of enamel, latex, oil paints, stain and varnish
• Jen does not recommend using its products with shellac or lacquer
• Less spatter and a cleaner finish than a nap roller on smooth surfaces
• Roller cover only; fits all standard 4" roller holders
• For use on smooth surfaces
• Throw-away construction -- no cleanup required
• Width: 4"
• Made by Jen Manufacturing, a Worcester, Massachusetts manufacturer since 1957

Best For: Cabinet fronts, shelves, small doors, closet interiors, and mid-scale finish work where the 3" mini would be slow and the 9" would be unwieldy.