10'' polypropylene block, filled stiff blue polyester. The D4 was one of the first all-plastic hygiene hand scrubs made by Hillbrush some 45 years ago. It has been one of our most popular products ever since. This rugged brush is designed to work and to last. The angled material at the sides and front is superb for cleaning in hard-to-reach corners, while the gripped handle is comfortable to use even in gloved hands. There is a resin set version, #D4RES, and a softer version #D5. See also #D4MDX, and AMD4.