The FLEX Power Tools STACK PACK Side Mount Rails, No. FS1608-2, are designed to securely attach to the sides of STACK PACK tool storage boxes. These rails feature a quick-clamp mounting system that allows easy, tool-free setup and adjustments of TRACK-LOCK hooks and racks. Each Side Mount Rail supports up to 30 lbs. so users can hang, mount, or attach power tools and equipment to their STACK PACK setup.