Aqua Lung MK2 Undergarment JacketAt the heart of our Glacier line of undergarments is the MK2 Jacket to keep your core warm. We've designed it for versatility, so you can layer up or dial it back to suit a wide range of diving conditions; it converts to a vest that can be worn with our MK2 John. Fully equipped, it has everything you'll need and more. Part of our Glacier Series undergarment line. Features: Chest Pocket. Zippered chest pocket provides quick access to small items