Abstract: A device for permitting the simultaneous transfer of a plurality of silicon wafers from one wafer carrier to another, and particularly for permitting a mass transfer between carriers having different wafer spacings. The device comprises two rectangular frames with a portion of the upper frame extending into the lower frame. Both frames are provided with a plurality of wafer slots although in the lower frame there is a greater number of slots and they are more closely spaced than in the upper frame. Each frame is adapted to interface with and be releasably secured to a carrier having a like number of wafer slots. The upper frame is slidable within the lower frame and means are provided to register its slots with different groups of the slots in the lower frame.