Ultra Clean Universal Foam Projectile, 6mm (100/bag)The projectile cleans by being compressed against the internal surface of the hose, tube, or pipe. This pressure is achieved as the projectile is approximately 20% to 30% larger than the internal diameter of the hose, tube, or pipe. For instance, a 2 (50mm) projectile is recommended for a 1 1 2 (38mm) hose. Individual circumstances may require a smaller or larger projectile. If the projectile is too large it will not leave the nozzle, and if it is too