Tripp Lite by Eaton SmartRack 12U Vertical Extension Top Hat for Server Racks - 42 in. Deep, Doors & Side Panels IncludedThe Tripp Lite by Eaton SmartRack 12U Vertical Extension Top Hat is the intelligent solution for growing your server capacity without expanding your floor footprint. Designed for data centers, server rooms, and network closets where space is at a premium, this 12U top hat expansion attaches securely to the top of an existing 19 inch SmartRack system, effectively adding vertical rack height without sacrificing accessibility, security, or organization.