Get ready to experience what proper alignment feels like. Your whole back will thank you To size yourself properly, start with the shirt size you usually wear. Keep in mind CoreXO does not cover the breast area, so these are not a factor. Sizing chart. You can change your size selection during the post-campaign email communication as well, and ask any further questions you may have about the size you chose. Size Chart Guide: Step 1- When choosing a size, start by measuring your chest right under your armpits and above your bust/breast. This will be the guiding measurement for choosing your CoreXO. Step 2- Measure your waist about 4 inches above your belly button. This is where your CoreXO waistband should be placed. Notice the size chart has wider ranges for the waist on each size since the waistband is flexible and includes extra length for adjustments. Accessorize any outfit or wear it seamlessly under your clothes. CoreXO's patent-pending design is made with the softest yoga/compression pants-like material. This means that it is stretchy and super soft on your skin without sacrificing function. Pull down the shoulder straps for an extra shoulder & neck stretch to control and further relieve tension from your entire back. Close the patent pending “Lats Zipper" to engage the Lats, mid-back, and cup back fat. CoreXO engages the lats with a vertical "lats zipper", expanding the chest to increase respiratory capacity It also cups "back fat" to support shapely rolls that get in the way of proper alignment and engages the abdominals supporting posture from your core. You’ll get a level of support you have never felt before! CoreXO’s shoulder straps are positioned strategically to pull the shoulders and neck into alignment. This causes an awesome relief of tension on shoulders and neck accumulated from hunching over our computers and cellphones, poor sleeping positions or just living life. When your body gets tired at any level, or if you need extra support at the end of a long day, your CoreXO adapts with you. With CoreXO's beautiful styles and adaptive design you can train at the office, the gym, or out in a social event to continue enjoying great posture everywhere you go!