The Alaska Guide Creations Ravus Side Pocket is a stand alone zippered pocket that can be attached to any belt, bino harness, backpack, etc. However, it was designed to attach the side of the Ravus Bino Pack. The pocket features dual zippers that make it ideal for right and left handed users. It attaches to the side of the Ravus with one strap affixed with a snap closer and one gatekeeper. 
The gatekeeper would not be used if attaching to a belt or other strap.
The Ravus Pocket measures 5-inches tall x 3-inches wide x 1.5-inches deep and is perfect for storing small electronics, knives, calls, wind checker, or any other small necessities.