Protec's Trombone Mouthpiece Protector Brush is uniquely designed to clear back bores while simultaneously protecting the end of the shank. By keeping the brush inside the mouthpiece after every use, the handle protects the end of the shank from dents. Highlighted Features Uniquely designed to be stored in the mouthpiece. Protects end of the shank from dents when kept inside after every use. Made of soft nylon bristles to clean the back bore.