How It Works

  1. Contaminated air passes through the
    viral filter with sub-micron level capture.

  2. Fan pulls in outside air. Circulates clean air. Provides positive air pressure.

  3. Person exhales CO2 through a surgical mask.*

  4. CO2 is continuously vented out rear flutters valves.

Fan is powered by USB battery pack in the user's pocket.

*It is best practice to always wear a surgical mask with bunnyPAPR™.
The diagram shows shows valves for the exhaust. Our newer model (July 2020) can use filters on the exhaust instead, eliminating potential viral shedding by the user.

Better than an N95

The bunnyPAPR™ offers effective protection and extended comfort. The units use viral filters that exceed N95 protection for particle size filtration and provide a physical barrier against aerosol, droplet, and splashs threats from all directions. Plus the bunnyPAPR™ has no fit issues that decrease the efficacy of other emergency PPE options.

Non-bunnyPAPR™ PPE Options

N95 Masks

  • “Gold standard” protection. Proven technology.

  • Subject to global shortages and vulnerable/weak supply chains

  • Other issues:

    • Susceptible to leaks and seal failure

    • CO2 build up can cause headache and confusion

    • Uncomfortable: Hours of wear causes injury to facial tissue

Powered Air Purifying Respirator (PAPR)

  • Established technology used in 1000s of hospitals

  • Cost of ~$2000/unit makes them cost prohibitive

Snorkel Masks

  • Combines a snorkel mask with a viral filter

  • Difficult to source and procure in the numbers needed

bunnyPAPR Benefits

  • bunnyPAPR™ uses viral filters that exceed N95 protection for particle size filtration

  • Passes the same N95 fit test (QLFT) as certified, FDA-approved PPE

  • Protects against aerosol, droplet, and splash threat from all directions

  • Wearer can easily carry out typical operating room procedures, intubations, extubations, and more

  • Provides protection even for those with glasses, facial hair or people who simply cannot make a good seal with N95 masks

  • No contact with skin means no painful mask marks and/or contact dermatitis.

  • At only 200 grams, wearing the unit feels similar to wearing a baseball cap.

  • Inspiration is without effort. Fan does the work of pulling air through filter.

The bunnyPAPR: Parts & Process

Full-Build and use instructions at


  • Loop with 12V fan mounted.

  • Plastic bag with view window

  • Bag flutter valves x 2

  • Bag filter 22 mm adapter

  • Anesthesia circuit virus filter (99.99% efficiency)

  • Strap to secure bag around neck

  • 12 volt power source
    (alternate: USB battery pack with 12V adapter)

Hood Bag

  • Bag needs to be large enough and well sealed. Many readily available polyethylene bags are usable.

  • Adequate seal and gas flow are readily readily monitored by bag's positive pressure inflation.

  • View window is easily added to any bag using packing tape and a piece of transparent plastic sheeting such as laser print film or scavenged mask visors.

  • Because Bunny PAPR uses a large volume, compliant bag, wearer can take full size breaths. As a positive pressure system, wearer is also spared the work of pulling air through a filter.

  • Clear presentation covers are an excellent, stronger and more optically clear alternative to laser transparency sheets. 8.5 x 11 inch cover makes two large view windows.

  • Easy to obtain and disposable.

  • Alternate: A clearview bag made of BOPP material.

The Loop

  • Loop flexes to conform to most head sizes.. Hooks in rear of loop allow elastic bands for preferred tension and size.

  • Mounting slots for top of head, 51 mm blower fan mounting band. Insert and click band into position.

  • Expiratory ports for flutter valves

  • Hooks for tension band.

  • Oxygen supplied configuration is deprecated. Latest Bunny PAPR's omit O2 tubing clips.

Fan Mounting Band

  • Blower fan is mounted atop height adjustable band.

  • Band inserts into mounting slots on each side of loop. Insert into slot and click to desired height.

  • For those needing to wear the PAPR for prolonged periods, adding a thin piece of neoprene foam below the fan mount improves comfort. You can see the edge of black neoprene under the fan mount. Bolts pass through the neoprene and hold it in place.

  • Old-style mounting points were actually downward pointed hooks. If using version with hooks, always engage bottom end of mounting point first. Then snap the side and top of band opening into place.

Expiratory Flutter Valves

  • Expiratory flow is through one way flutter valves. These screw onto the loop and create an airtight, penetration through the bag.

  • Flutter valves are fashioned from a cut-off glove finger rubber banded onto Flutter Valve Penetrator. End of finger is cut to allow air exit, but stop reverse inflow.

  • Older, round flutter valve fittings also required addition of a valve deflector piece to pre-bend the glove finger.

  • Bunny PAPR with correct inflow rate maintains continuous positive pressure. The flutter valves should rarely if ever need to close.

  • Test that your airflow and expiratory fittings configuration maintains bag inflated even during inspiration The bag should only collapse inward about 1 cm.

bunnyPAPR™ is free Personal Protective Equipment for practitioners, patients, and frontline workers who don’t have access to FDA-approved equipment. It is not currently FDA-certified and therefore use is at your sole risk and discretion. Always consult with your infection control department.

It is always best practice to wear a surgical mask with bunnyPAPR™ and perform an N95 leak test upon first wearing.

For more detail, please consult: Quick Start Guide OR Full disclosures document (10+ pages).