The file 'Exhalation Valve Diy Mask 3D Printed MSK P1 P2 P3 Corona Virus 3D Printer Model' is (pdf,stl) file type, size is 1.7MB.
VIDEO TUTORIAL
https://www.youtube.com/watch?v=-Pf-NryzXIc&t=12s
I used 4 skottex sheets :
https://www.amazon.it/Scottex-Duramax-Carta-Resistente-Superfici/dp/B07B68TC9M?ref_=s9_apbd_obs_hd_bw_b6ylxh1&pf_rd_r=ABTG0SZZ8G06SPC4MG6W&pf_rd_p=9af8ef82-f383-51f9-b7ab-3cd8d76da0a9&pf_rd_s=merchandised-search-10&pf_rd_t=BROWSE&pf_rd_i=6394808031