The M21+™ Universal insert allows for any mask, including cloth, surgical, or N95 masks. The mask slides easily into any of these masks.

This insert is most commonly used with cloth masks, which come in many different thicknesses and foldovers. Therefore, if you are using the M21+™ Universal, we are pleased to offer the following tips for adding M21+™ to your cloth mask:

• • Take your time when raising the outer rim of the M21+™ Universal to start feeding the material through the slot
  • Use your thumb.on top and bottom of the plastic to support the end corners of the slot when pulling the material through the slot on each side. Although the M21+™ Universal is made from a durable plastic material, this additional caution will help prevent it from potentially snapping.
  • Feed the mask material through the slot side-to-side until the cloth is fully engaged through the slot, flat side-to-side, and slowly pull the cloth through the slot slowly supporting the slot corners.
  • Take your time - cloth mask materials are thicker than other reusable and disposable masks and often have very thick edging.