Stihl ADVANCE X-Flex AP Holster With Connecting CableADVANCE X FLEX AP Holster with Connecting Cable: For the X FLEX harness system The ADVANCE X Flex holster with connecting cable is part of the STIHL ADVANCE X Flex modular harness system. It allows an AP battery to be stored on the operators hip and plugged in to the machine via the cable, reducing the weight of the tool. The battery is kept securely in place with an elastic strap, and openings on its underside allow dirt and water to escape.