The NP1 and NP2 versions have a slot damper installed inside, used to regulate the air flow through the ventilator. The external intake vent is equipped with a protective mesh and a rain hood. The air intake and the diffuser are connected by a telescopic cuff adapted for mounting the set in a building partition with a thickness of 300 to 550 mm. There is an air filter and an acoustic silencer inside the telescopic cuff. The NP1s and NP2s are available in several variants: