The BEST 4T, introduced in the 1930s, was an early example of heavy-duty auxiliary locking hardware that, by today’s standards, would be classified as a deadbolt. At the time, however, it was marketed as a mortise lock and was commonly used in commercial and institutional settings for added security. A “night latch” version featured a turn knob on one side, offering convenience alongside robust protection. The 4T reflects BEST’s early innovation in lock design and helped lay the groundwork for security expectations that would later be formalized in BHMA standards.
