This is a full concealed, heavy duty, aluminum continuous gear hinge with a 1/16" door inset. Safety hinge application when used without a frame stop. Used primarily in schools nursing homes and day care facilities to avoid fingers and/or other objects being closed in the door; 9/16" gap between frame leaf and door leaf when door is closed. Fire rated for use on metal swing type doors rated up to 90 minutes and wood swing type doors up to 60 minutes. Continuous hinges alleviate most common alignment problems.