Velcro closure for pulling on & off easily. In addition to giving the wearer support & protection, the unit provides therapeutic warmth to the shoulder & upper arm. Measure around the chest 35-39". R0000 DEIG5, Thinskin Pro is especially designed to be worn close to the skin & allows complete freedom of movement. It delivers superior moisture management & ventilation to improve airflow for increased comfort. It will keep you warm.