The Penn Elcom R1297-DV190-K is an individual 7.5" (190mm) ventilated divider panel explicitly designed as an add-on or replacement piece for the Penn Elcom R1297-DVS vertical mounting shelf series. It allows you to expand your rack capacity if you need to subdivide your shelf space into more slots than the standard 5 dividers included with the core system kits. They allow you to mount multiple thin devices like mini routers, micro PCs, or external hard drives side-by-side and each unit comes with all the necessary mounting hardware required to secure it to the slotted base of the shelf.