They are constructed with 300-Series stainless steel materials and therefore resistant to atmospheric corrosion, foodstuffs, sterilizing solutions, many organic chemicals, dyestuffs and a wide variety of inorganic chemicals.

An external adjustment screw accurately varies orifice opening from closed to full flow as required. The final position can then be locked in place by the jam nut. 

The surrounding sleeve of stainless steel element reduces exhaust air noise. And it is protected by the integral stainless steel shroud/cage. 

Unit should be mounted in a protective position free from excessive vibration. Use wrench on hex head to tighten unit to the device. All units contain 70 micron filter element.