Vintage Dictaphone Fire Protection Device with NFPA Booklet (1952)

Vintage Dictaphone Model-B Fire Protection Device.   These items were from my mother's estate.  The house was built in 1952 and the detection system was installed when the house was built or shortly after.     The device was an extra sensor that was stored in the basement.  In my youth in the 1960's these devices were wired in each room.    I believe this is a heat sensor but I'm not sure. Vintage booklet from the National Fire Protection Agency about the benefit of installing automatic fire detection devices in the home.   Not all pages photographed.   12 pages.  Dated 1952.   The author writes at the end of the booklet that he hopes that the fire protection device industry never suggests to the insurance industry that they offer a premium discount for the installation of such a device because what they have to sell is beyond the value of all insurance.