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. 2022 Jan 21:1–5. doi: 10.1017/dmp.2022.23

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© The Author(s) 2022

This article is made available via the PMC Open Access Subset for unrestricted re-use and analyses in any form or by any means subject to acknowledgement of the original source. These permissions are granted for the duration of the COVID-19 pandemic or until permissions are revoked in writing. Upon expiration of these permissions, PMC is granted a perpetual license to make this article available via PMC and Europe PMC, consistent with existing copyright protections.

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Figure 2. — Top: For visualizing the size of the gaps, 1.5-mm diameter and 2-mm diameter dots placed on an adult female finger. Bottom left: A steel rod spacer placed through the material of the mask. Bottom right: The 3D printed resin spacer held against the edge of the mask. A small hole in the middle of the spacers allowed air to flow through.