The SMART Edge Roller is designed to make cutting-in around windows, doors, trim and corners fast and easy. It provides a controlled and continuous flow of paint from the handle to the roller, eliminating the need for messy, dripping brushes and paint trays. Plus, there is no more taping required. The key is the Twist and Trim Tool which has a Trim Guard and 3 micro brushes for painting right up to the edge of the surface, giving you a consistent finish for your entire painting project. The guard prevents the roller from touching the trim. The Trim Guard quickly folds away for regular rolling. The paint tube holds 6 fl oz. and its 3" x 3/8" roller allows you to edge approximately 96 linear feet in a single fill. Trim a 12' x 12' room in approximately 2-3 fills.