Pass Boxes, are so designed to handle the soiled materials from sterile areas, to transfer to an adjacent room-without compromise in air quality. The special design of doors allows opening of only one door at a time. Pass boxes are available in two models; 1) Static pass boxes and 2) Dynamic Pass Boxes. DIGITAL ELECTRONIC CONTROL SYSTEM INCORPORATED. The SS double shell, made of SS 304, 1.2 mm thick material.