Tighter polycarbonate nozzle (air seal nozzle) for M4A1 / M16A2 weapons. Length 21.45 mm. This nozzle has a different nozzle tip than the standard one, which, unlike the normal nozzle, pushes the bullet 1.1mm forward, improving functionality and airflow, especially when firing in bursts. The nozzle has an O-ring that improves air tightness.