Face Mask Using 58mm Diameter Filter

Updates:
2020-05-03: fix floating strap mount, thanks to jpsaila for pointing this out
2020-04-25: flex friendly version https://www.thingiverse.com/thing:4316736 :
2020-04-18 : minor updates, added narrow versions, step files
2020-04-06 : new cap and cover for thicker pads
2020-04-05 : new grill and strap mount design
2020-03-25 : uploaded new version of 2 point strap mount, also in 4 sizes: the original (100%), 105%, 110% and 115% scales, all using the same filter cover
2020-03-25 : uploaded version with 4 point strap mount, in 4 sizes: the original (100%), 105%, 110% and 115% scales, all using the same filter cover
2020-03-21 : small improvement on the strap mount, STEP files uploaded for those who want to remix, bigger version 5% bigger than the original

2020-03-19 : based on Euter's comment, sealed up the mounting and strap holes. Redesigned strap mount.

Overview:
This face mask was originally designed for circular cotton pad as filter. Cotton pad is roughly 58mm i