Bring the Travel Bottle from Herschel Supply Co. in your carry on for a quick weekend trip. At only 3oz, they're small enough to make it through TSA, but large enough to hold enough shampoo, conditioner, body wash, or lotion for your whole trip. A handy suction pad on the back allows you to stick the bottles to the shower wall at your hotel and the leak-free twist cap prevents you from losing any precious liquids.