RFH 355nm UV laser marking on N95 face mask for QR code As the main material of the N95 face mask, meltblown cloth has a thin surface and cannot be processed in a hot environment casually. Other laser light sources will produce high temperatures during processing. Only short-wavelength (355nm) ultraviolet lasers have little thermal impact and will not produce high temperatures during marking. What’s more, it will not cause damage to the N95 face mask.