The Pass Box is an auxiliary equipment of the clean room. It is mainly used for the transfer of small items between the clean area and the clean area, and between the clean area and the non-clean area, so as to reduce the number of openings of the clean room and reduce the pollution to the clean room. reduced to a lower level. The transfer window is made of stainless steel plate, smooth and clean. The double doors are interlocked with each other to effectively prevent cross-contamination, and are equipped with electronic or mechanical interlocking devices.