Sephora used to carry 4-mm-wide elastics that were basically invisible, snag-free, super stretchy, and surprisingly strong. They were magical, and they became the ties I reached for most, whether they were for casual ponytails, unobtrusive braid ends, or strategic holds for fancier ’dos. They do stretch out quite a bit, but if you leave them overnight they usually bounce back! I nearly cried when Sephora stopped carrying them, but these Blax hair elastics are the next best thing I’ve found. (In fact, the maker of Blax hair elastics responded to an Amazon customer question stating that they produced the Sephora ones under a private label for the cosmetics giant!) I have medium-thick, fairly smooth hair, and these tiny things defy physics when they hold a ponytail. The elastics are too little to keep on a wrist, though, so it’s way too easy to lose them. Even though they’re not cheap, I recommend stocking up!