In the process of material transfer from unclassified area to classified area pass box used. Pass box is rectangular box with two or three doors. The doors are interlocked such a way that doors cannot be open at the same time, due to which pressure losses and bacterial contamination doesn't take place throughout the material transferring process.

The prevention of simultaneous access of doors is been achieved by our Pass Box controller by ensuring that when one door for a Pass box is open then other doors closed.