Product details:

While bolt is held fully retracted, a reverse turn of the key retains the bolt and thus allowing the door to be free swinging with two-way traffic for hospitals, banks, stores, and other buildings which require free entrance at certain times and exit-only at other times. It is easily interchangeable, without stile modification with any MS1850A or MS1850S Deadlock of same backset and faceplate shape. However, they donot provide the same maximum security level as the MS Deadlock.