STACK PACK COMPATIBLE – Fits with select FLEX STACK PACK tool boxes. Ideal for the Rolling Tool Box (FS1101) and Medium Tool Box (FS1102) VERSATILE MOUNTING – Securely mounts batteries inside STACK PACK tool boxes, on outer rack attachments, or on the wall STORE UP TO THREE BATTERIES – Compatible with FLEX batteries only EASY ACCESS – Minimize downtime on the job with easy access to batteries mounted inside or outside your STACK PACK QUICK INSTALLATION – The Battery Holder can be installed by sliding onto side or front rail racks, or fits inside the FLEX STACK PACK Rolling Tool Box (FS1101) or Medium Tool Box (FS1102) FULL RANGE COMPATIBILITY – STACK PACK toolboxes, organizers, accessory cases, and toolbox attachments are endlessly configurable across the full STACK PACK system