Abstract: This disclosure depicts a plug-in module card holder for supporting a plurality of circuit cards, each of the cards having a securing level with a notch. The plug-in module card holder comprises at least two card shelf plates and a strengthening strip for each of the card shelf plates. The card shelf plates are oriented in a parallel relationship and each has one or more grooves. A circuit card is retained in one of the grooves in each of the two card shelf plates. Each of the card shelf plates has an outer edge having a tab with first and second offset channels. The strengthening strip has an engaging portion consisting of first and second offset ridges for engaging the first and second channels of the tab of the card shelf plate. The strengthening portion also has a retaining portion for mating with the notch in the lever and thereby securing the circuit card in the circuit card holder with a cam action.