USEFUL CHICK STUFF. Boost-its Full Cup Bra Inserts increase your breasts by one cup size. The million-dollar boob-job question. Would you, wouldn’t you? And what if some days you want them, other days you don’t? How to decide? Well now you don’t have to. Slipped inside your bra, they feel and look just like the real thing – only bigger. They’re mood-uplifting, confidence-inspiring, and super-discreet. For all these reasons, we love our Boost-its. 1 Re-usable pair per pack.