**Please note item does run SMALL** About this item SNUG & TIGHT FIT - PLEASE SIZE UP: If you're in between sizes or want some extra room we recommend picking 1 size larger then your normal size. This Sauna Shirt works best when it fits closely to your body so it can really work it's magic and get the make every step count. SWEAT MORE - Sweat hard, keep dry: this garment was designed to increase perspiration but keep it all inside. Kewlioo sauna suit stimulates sweat during exercise 3x times more than normal clothing to aid in burning fat by preserving body heat where it matters most: your abs, lower back, chest & waist. The waist slimmer makes you sweat in the right spot using the comfort antislip waistband that is absorbing sweat so you're always dry on the outside. FAST RESULTS - Maximize heat exposure and helps burn more calories FASTER by deploying evolutionary pressure on your body during workouts or everyday activities and forcing it to adapt. Speed up recovery time: keeps your muscles warm so you can ease in and out of physical exercise and help prevent muscle or joint injuries.