The Wooster 9 inch Professional Roller Frame has a unique retaining spring that securely holds the roller to prevent it from walking off a cage. After painting， the cover removes with a single rap of the frame on the edge of a paint bucket. Its twin bearing system eliminates friction that causes graying and streaking in paint. The cage provides uniform， full-span support of the roller cover to prevent it from going out of round. Its handle is threaded for easy attachment to all extension poles.