Cumbersome but effective [SEP] The shield works very well, when the mask is being worn for longer periods or during exercise. The problem is there is no easy way to secure the shield in the mask, meaning if one attempts to wear it to a restaurant or other location where intermittent wearing is allowed, keeping the two together and aligned properly is an issue. Securing to the shield to a reusable mask semi-permanently (sewing or taping) helps, but makes washing and sanitizing more of a problem. Still, the idea of keeping the mask itself away from your mouth and nostrils is a good one.  Is it worth the effort? That is up to the user.