Deckers new Grip-Fit Brush blocks are designed to fit your hand. Ordinary wood blocks disregard the shape and size of human hands. Since Grip-Fit blocks are molded polypropylene, they can be made in a truly utilitarian, comfortable shape that has to be experienced to be appreciated. The polypropylene handle will not rot or mildew and is not harmed by caustic solutions. Medium - Blue Synthetic Bristles. Gets the job done fast. Also makes a dandy general purpose scrub brush.