NoBoxes

Being adept at doing surgical preps, I have in the past used a straight razor from the minor surgery kit in my trauma bag for shaving in the field.

Nowadays, in the outer pouch of a gas mask carrier, I keep a heavy duty gyroscope [single head, rotary blade] shaver that requires just pulling a cord to dry shave under most conditions that a gas mask would be used (the mask isn't effective if facial hair breaks its seal against the skin).

At home, I'm still using an old Atra Plus with shaving gel in the shower.