The Graham Field 3419 (Grafco/Labtron) is a specialized, dual-diameter cleaning instrument designed specifically for the rigorous maintenance of laboratory pipettes. This 17-inch brush features a unique two-stage bristle configuration to handle the varying bore sizes of common lab pipettes: a larger bristle section for the upper body and a smaller, more narrow section for the lower stem. The soft white nylon bristles are mounted on a flexible, galvanized wire handle, allowing the brush to reach through long, narrow instruments while providing effective scrubbing power without damaging delicate glass or plastic surfaces.