This card frame packaging system fits up to ten 5.25″ x 1.5″ x 7″ modules into a standard 3U rack space. Mounting rails, end pieces and rack ears easily bolt together to form a sturdy cage. The single, double and triple wide black anodized blank panels are industry standard. Pre-punched with mounting holes. #4 “L” brackets and hardware for circuit board mounting are included with the panels.