The Duchess of Cambridge wore the adult version of the Amaia London Reusable Cotton Face Mask (£12) when she visited Baby Basics's Sheffield centre in early August (they also come in children's sizes). Catherine wore the "Pepper" Liberty print (shown here), which is unsurprisingly sold out, but there are several patterns still available on the brand's website with the ability to preorder the out-of-stock designs.
The double layer, 100% cotton masks — which are designed in London and made in Spain — feature filter pocket, and include 5 filter refills (the brand also sells a pack of 25 filters on the site). Not only that, but 30% of the proceeds will go to NHS Charities Together.