I bought the Adidas ones, paired it up with a disposable paper carbon filter and one of the mask straps that hold the 2 ear loops round the back of your head so they don't cut into your ears.
Links to the stuff below,
https://www.adidas.co.uk/face-covers-m-l-3-pack/H08836.html
https://www.amazon.co.uk/Anti-Tightening-Protector-Decompression-Accessories-Extension/dp/B087LYJHMV/ref=mp_s_a_1_5?dchild=1&keywords=mask+clips+for+ears&qid=1594651318&sprefix=Mask+&sr=8-5
https://www.amazon.co.uk/Activated-Carbon-Replaceable-Protective-Outdoor/dp/B088D9ZH5S/ref=mp_s_a_1_4?dchild=1&keywords=Paper+mask+filter&qid=1594651269&sr=8-4