Fire doors are usually used in emergency passages in communities, shopping malls, offices, etc., so if there is a fire door, there must be a fire door lock. Today we will learn about the specifications of the fire door lock body. Commonly used fire door lock body specifications are usually 55*72mm and 60*72mm. The lock body as an important part of the fire door is mostly made of stainless steel 304, because the stainless steel lock body is the most cost-effective compared to other materials. Installation The latter is also more durable.