Summer outfits can be tricky. Between lightweight fabrics and clingy silhouettes, finding undergarments that actually stay invisible is a challenge. That's why so many shoppers swear by the 24/7 T-Shirt Bra from ThirdLove, a go-to essential designed to smooth, support and completely disappear under your favorite warm-weather looks. When it comes to getting dressed in the heat, what you wear underneath matters just as much as the outfit itself.