This is designed for holding one 300 cartridge retainer when using Loctite 3 axis robots. Due to the size of the 300 ml cartridge, it is not compatible with 4 axis robots. The C rail connection allows for more than one bracket to be used when using 3 axis robots. This allows for multiple dispense points to increase throughput. A mounting rail or plate must be purchased separately to mount the brackets on the robot.