The Chest Pocket / NDM 2 is the optimal attachment for the person that wants to access either soft or hard surface sport bottles without having to open a pocket or take off the backpack. The attachment can be used on the No Dancing Monkey™ 2.0 and No Dancing Monkey™ 2.1 harnesses and is simply attached by a four (4) plastic clips. The pocket is approximately 17 cm / 6.7" in height and 8 cm / 3.2" in width. This product is compatible with the following models: Hajker (NOT Winter). Hajker Ultra. Hajker PRO. Tracker. Shred. Flow. Core. Watt. Note: The Chest pocket / NDM 2 canNOT be used at the same time as the Action Camera Harness / NDM 2.