All V-Series Supplied Air Valves require a supplied air hose to complete the NIOSH-approved respirator system. These hoses are available in many different lengths and are sold separately.
3M 37019, Versaflo Air Regulating Valve Assembly V-300/37019(AAD), 7100077491, 1 EA/Case
$224.35
Factory Stock, 7-10 Day Leadtime, Priced Per Case
Allows the worker to set the airflow to the most comfortable level. Includes the valve and waist belt. It is strictly a regulator and will not warm or cool supplied air to the worker.

Dynabrade 15324 1" W x 2" L Hard Platen Pad 5-Pkg.
3M 29095, Exhalation Valve Cover 7918, 7000126043, 20 EA/Case 
