This was a great model to complement the masks I am sewing! I printed these on a MK3 and MK3S using PLA. It took about 1.5 - 2 hours with 5-6 of these placed on the bed. I found that printing these with PLA is much more efficient with releasing off the Prusa flex PEI steel sheets. I have another printer (Matterhackers Pulse) with a flexplate and Buildtak surface printing this model x 6, but its harder to remove off the bed. I suggest using a strong spatula that will not scratch your print bed much in order to efficiently remove the prints if bending a flex steel sheet will not completely remove the prints.I have also printed these in PETG and I recommend cleaning your PEI sheet with IPA alcohol for best adhesion and a paper towel prior to every print.