||Use the Rail Seal Kit on the cabinet's front pair of quipment mounting rails with Snap-In Filler Panels to create a front/rear (cold/hot) airflow barrier within the cabinet. Each Rail set Kit includes four half-height panels, edge seal and installation hardware. Each panel has three round 2.8" (71 mm) diameter cable grommets that align with cable openings in the mounting rail. Select to match cabinet width and rail height. The Rail Seal Kit cannot be used with Cable Ring Kits. Color is black.