If you're taking a shaving device of any sort on your backpacking trip, you've missed a core lesson of the ultra light dudes.

They never said they were packing for a backpacking trip.

Ah, true. I made an assumption.

Wouldn't it be logical that ultra light people have no body hair left? And want to keep it so? After all that is lot of grams...

Well it's only useful if you go on such long hikes that the weight of your hair exceeds the weight of your shaver

Not to mention all the energy loss from air friction!

just think of all the excess weight of dead skin cells covering your body!

Should be one safety razor - just the blade. Just need a steady hand...

You're budgeting for the weight of a safety razor?

Surely the hunting knife you use to kill your dinner when combined with the mirror you use for starting your forraged twig fires, that would be the ultimate solution.

...or just not shave for a few days. I guess you could do that too.

Think of the weight of all the extra hairs though.

That's a good point. Personally, I compensate for that by drinking slighly less water each day.

It's a trade off but I think it makes perfect sense after a few nights of not-sleeping directly on the ground under a miniture dyneema tarp.

About 12 days per gram.