LCN is a door closer and accessories manufacturer, that has been delivering quality products since 1926. The LCN fusible links offered by RBA Door represent the full range of the LCN line and can be used as door closers on fire doors. The fusible link is designed to melt when they reach a temperature of 135 degrees. When the link melts, it releases the hold open mechanism, and the door closes to contain the heat source. The fusible link door closers were used from the 1940's to now, but have seen there usage declining due to the modern fire alarm systems that are wired into the door closers. At this point LCN is one of the only companies still making Fusible Link door closers. Since 1970 Robert Brooke has prided itself of offering the best in door closers and all associated parts and accessories.