The "MalaMask" Project (N95 Alternative Filter)

The "Reusable Mask with one time use filters tested at N95 filter specs".

Request Product and Supplies

*** 202 Masks and 948 Filters Requested *** *** 202 Masks and 948 Filters Delivered ***

Due to high demand of PPE at this time we will do our best to fulfill the orders that are placed. We will contact you regarding fulfillment and arrange delivery.


A mask is only as good as the filter that it uses... Filter First, mask second!

IT PASSED! We have found filters that have passed the 95% efficiency at the 0.3 micron spec! See the conclusion in the filter research document.

Welcome to the "MalaMask" project, a project focused on giving healthcare providers and first responders access to alternative PPE when N95 masks are not available. The reusable MalaMask holds a one time use filter (not included).

This mask project is completely open source (CC BY-NC license). We want to share this with the world to help protect the healthcare workers and first responders that are taking care of the people with this horrible virus. Feel free to distribute, share, and print your own under the MalaMask legal agreement (see link here). If you share this, please link back to the River City Labs wiki.

See "The Playbook!" section below for all research, documents, videos, and how-to's pertaining to this project.

Please note this mask project is formally defined as a "Reusable Mask with one time use filters tested at N95 mask filter specs". Disclaimer: River City Labs is a MakerSpace organization that is 100% volunteer run and operated. We are filling a need in the community. The MalaMask is not medical grade. We have done testing (see link here) and believe it will help when no other medical equipment is available. We do not certify the design or components will operate properly or satisfy any regulatory requirements.

The Filter

The filter is comprise of 5 layers of Merv 13 and 2 layers of cotton with a density of 0.6mm-0.85mm thick @ 1lb 9oz of pressure over a 3mm by 10mm area.

Have you had this filter professionally tested? YES! See the results.

How efficient is this filter when lab tested? Average of 99.9697% efficient over 3 samples at the 0.3 micron spec @ 32 liters/minute. See the results.

What is the best efficiency you have found? Average of 97.66% efficient over 5 samples at the 0.3 micron spec. Average of 93.067% efficient over 3 samples at the 0.3 micron spec over 80 minutes. Efficiency Range of 92.5% - 98.1% over all 8 samples. 5 of the 5 samples were at or above 95% for initial efficiency. Then why not this combination... well you have to balance breath-ability. See the results and See our filter research.

Where can I find the supplies needed to make this filter? See our Material Sourcing doc or you can request filter media through our "Request Product and Supplies" form. We also have a DIY section in the manufacturing resources document where you can make these yourself.

Is this the right filter and mask for me? A majority of people do not need this level of filtering and a sealed mask. If you are exposed to an aerosol environment, a "Maximum Filtration" mask and filter is appropriate. Typically people that are exposed to these conditions are going to be in emergent healthcare, ICU healthcare and first responders (Fire and EMT). For the majority of people who are not exposed to these conditions, a "ASTM Level... [1-3]" mask / alternative would be appropriate. See River City Labs "Midwest Mask".

How Can I help?

The Design is final for 3D Printing. See our DIY section in the manufacturing resources document. 3D Printing masks aren't going to meet high demand in every situation so we are now moving to offset demand by looking at alternative manufacturing processes. Things like vacuum forming, CNC fabric cutting, CNC machining, CNC laser cutting, Resin Casting and Silicone Casting.

If you have services to offer in any of these areas and would like to be a manufacturing resource email

Part Donation Requirements

Any Donated parts will be no cost to the healthcare systems receiving them! We do have to keep our doors open so we are charging for transportation and supplies that are manufactured or we are sourcing people for paid supplies. River City Labs is a MakerSpace organization that is 100% volunteer run and operated. We are trying to give back and also give people the ability to make a living in a Country where millions of people are out of work.

There are a few critical criteria we will be strictly monitoring for any 3D printed donated mask:

  1. The print must adhere to the print settings mentioned below

  2. The print must not have any stringing material

  3. The print must not have ANY warping! This will cause a poor seal and ruin the effectiveness of the mask.

We will be inspecting every 3D printed mask that comes in for Quality Assurance to ensure we are providing only the best quality masks to our healthcare and first responder professionals.

Ship All Parts to: River City Labs Attn: COVID RESPONSE 7916 N Hale Ave Peoria, IL 61615

Required Print Settings

It is critical that these settings are adhered to. The mask and filter design is undergoing extensive testing and validation under these settings only. If any of these variables are changed, we lose all confidence that we'll achieve the tested and proven performance.

Mask Parts

  • Filament: PETG

  • Minimum Nozzle temp: 255c

  • Nozzle diameter: 0.4mm - 0.5mm

  • Infill: >= 20%

  • Layer height: 0.3mm or lower

Silicone Molds

  • Filament: PETG / PLA / ABS

  • Nozzle diameter: 0.4mm - 0.6mm

  • Infill: 30% (mold will last longer)

  • Layer height: 0.3mm or lower

Post processing

If your 3D print has some stringing, it is imperative to remove them. The approved way to remove the strings is light sanding with at least P220 - P500 grit sand paper.

The Playbook!

Designs, Assembly and How-To

Mask Design Printable Parts (Thingiverse / Youmagine / cult3D / PrusaPrinters)

Information: MalaMask 1 Pager Information: Material Sourcing Information: Manufacturing Resources Information: Sterilization Assembly: Mask and Filter Housing (Video, Document) How-To: Layer, Install, and Replace the Filter (Video, Document) How-To: Cut Mask Straps (Video, Document) How-To: Silicone Cast (Video, Document) How-To: Get a PPE Manufacturing Node Going

Supporting Information and Research

Filter Materials Research Public Project Folder Guide to Face Mask Selection (produced by CrossTex)

Supporting Videos

Part Fit-up Guidance Release, Waiver of Liability, Defense, Indemnification and Hold Harmless Agreement


FDA FAQ on 3D Printed PPE


Joshua Malavolti (Lead Design Engineer and Researcher): Jared Malavolti (Researcher):

River City Labs:

Project License

Open Source Licensed under CC BY-NC Project License can be found at

Project Contributors

Project Lead, Lead Designer, Lead Researcher: - Joshua Malavolti (@malamaker86) Awestruck by this project and glad to be on the right side of history.

Contributors: - Angie Malavolti (@malavo9) - Joe Spanier (@prcdslnc13) - Aaron Peterson (@aaronmakes) - Jared Malavolti - Phil Spengler - Sreeram Anikode Mahadevan (@sresam89) - Jay Babin - Eric Lien (@eclsnowman) - Lulzbot (@lulzbot) - Joe Mozzwald (@mozzwald) - Roger Wheeler - Alec Randazzo (@AlecRandazzo / Northern Virginia) - Kurt Lippert (Austin, TX) - Rob Mather (@Breaksteel / Connecticut) - Nova Labs (@nova_labs / Northern Virginia) Mask Name Contributed by... Alec Randazzo (@AlecRandazzo) @ Nova Labs MakerSpace in Northern Virginia. Thanks for helping nailing down a name!!! Special Thanks to all Financial Contributors. This project would not be what it is without your support! Thank you. Thank you to all the healthcare workers putting themselves in harms way to care for the COVID-19 patients and patients in general! You are the heroes!

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