GE 521BXT Category : GE I think that this smoke detector might be intended for use in security systems.
Fenwal MT4-24-LS-VAR Category : FenwalThis is like the Wheelock MT4-24LSM, except it is rebranded by Fenwal and has “AGENT” labeling. I assume the “VAR”...
Faraday 6234 Category : FaradayThis alarm uses an electromechanical horn. It is the same horn found on the Simplex 2901-9838.