The Allegro 9901 is a low-pressure, continuous-flow supplied-air respirator (SAR) with a full-face mask. Instead of filtering the air around you, it delivers a steady flow of clean breathing air to the mask from a remote source through an airline hose, giving full-face protection to the eyes and respiratory system. It's intended for work in atmospheres with airborne contaminants where a clean, approved supplied-air source is available — situations where air-purifying (filter) respirators are not adequate. The mask is molded from durable silicone rubber, uses a five-point harness, and is one-size-fits-most. It is NIOSH approved under Approval No. TC-19C-353.

The Allegro 9901 meets or exceeds NIOSH Approval No. TC-19C-353. Because it is a supplied-air respirator, the approval requires that it be used only with an Allegro-approved airline hose and a proper source of clean, breathable air. Using non-approved hose or air sources voids the NIOSH approval.

The masks are the same full-face silicone design; the difference is the air-supply pressure. The 9901 is the Low Pressure (LP) version and the 9902 is the High Pressure (HP) version. You choose the one that matches the approved supplied-air system you are running — low pressure for the 9901, high pressure for the 9902. Both share the same NIOSH-approved full mask, lens, harness, and seal design.

It provides a continuous flow of clean breathing air. Air travels from a remote clean-air source through an approved airline hose, connects to the mask via OBAC quick connects, and flows steadily into the full-face piece. A large-diameter contoured exhalation valve minimizes breathing resistance, and a removable valve cover protects it from dirt, paint spray, and freezing. It is not a self-contained (tank) unit and does not purify air — it must be connected to a supplied-air source with an Allegro-approved hose.

OBAC quick connects are the coupling fittings used to attach the airline hose to the Allegro 9901's breathing tube. Allegro designed them with a wide diameter and minimal air restriction so airflow to the mask stays high, and they let a worker connect or disconnect the airline quickly without tools. The down tube uses a 90° elbow that routes the hose over the shoulder and out of the way of work.

Yes. The Allegro 9901 uses a high-impact polycarbonate lens that meets ANSI Z87.1 for eye protection. It offers a wide, distortion-free field of vision and has an anti-fog and anti-scratch coating. The lens is fully replaceable, and disposable clear lens peel-offs are available as P/N 9901-25 to protect the lens from overspray and scratching and extend its life.

The Allegro 9901 is one-size-fits-most (Universal). It secures with a non-slip, durable rubber five-point harness and an adjustable buckle system to lock it in place. It includes a removable mesh hairnet that adds comfort, keeps the harness from pulling hair, and fits easily under a hard hat, so it can be worn on jobs that also require head protection.

The Allegro 9901 uses silicone rubber because it is durable and holds its shape even in extreme heat and cold, so the mask stays comfortable and seals well across a wide temperature range and in storage. The silicone is hypoallergenic and chemical/ozone resistant, and a double sealing flange plus a deep chin pocket give an improved, more comfortable face-to-mask seal compared with standard rubber masks.

No — it is a supplied-air respirator, not an air-purifying respirator, so it has no cartridges or filters. To use it you need an approved low-pressure source of clean, breathable air connected through an Allegro-approved airline hose to keep the NIOSH TC-19C-353 approval valid. It is intended for contaminated atmospheres where a clean air source is available, not as a standalone filter mask.

The Allegro 9901 Low Pressure Supplied Air Full Mask (Universal) is available at Industrial Safety Products (industrialsafetyproducts.com) with free shipping. Replacement and consumable parts are supported — for example, clear lens peel-offs (P/N 9901-25) to protect the polycarbonate lens — and the same platform carries the matching high-pressure 9902 version.