FlatPak™ Toiletry Bottles

I was skeptical about the soft sides but these flatten down to almost nothing once they're empty, which freed up so much room in my Dopp kit. The 90mL size got me through security without a second glance, and the soap didn't leak a drop in my checked bag.

Squeezed a week's worth of conditioner into one of these and it barely took up any room next to my toothbrush. The soft sides mean you can actually get the last bit out instead of tossing a half-full bottle. TSA didn't blink at them either.

The pouch design is genius—it lies totally flat in my carry-on, so I can fit three of them where one rigid bottle used to go. The soft sides make squeezing out every last drop of conditioner effortless, and after two weeks of flights, not a single leak.