a cassette for supporting substantially planar objects such as photomasks , glass plates or semiconductor wafers during processing . the cassette is composed of bars connected at each end to an endpiece . arms which form part of the endpiece are hinged to permit the side bars of the cassette to move inwardly and outwardly from one another when objects are inserted in the cassette . a bridge can connect an upper portion of the arms . the bridge can be used to lift the cassette and cause flexing of the cassette to ensure better retention while the cassette is being lifted .