Donut holes are fun, but they’re also underrated for a degree of sustainability genius. Why throw away perfectly good, usable dough when you could turn it into its own thing? We imagine this kind of logic was what Seokoo Yeo had in mind when designing a brilliant shampoo bottle that solves a waste problem and a travel problem.

While Carry On shampoo primarily comes in a large jug with a handle that makes it easy to carry around, it also fills its own void with a tiny elliptical travel-size version of itself. It’s easy to refill the mini bottle from the giant jug when it runs out of product, and sleek sans serif and calming colors make these intuitive designs look great to boot.