Graham Field Test Tube Cleaning BrushesThe Graham Field 3403 and 3404 series (Labtron) are essential laboratory tools designed for precision cleaning of test tubes, flasks, and small glassware. These brushes feature high quality bristles mounted on a flexible yet sturdy twisted wire handle, allowing for thorough scrubbing of narrow internal surfaces. The 3403 model provides an 8 inch total length, while the 3404 model extends to 9 inches for deeper vessels. Both designs include a radial