This key is an excellent old CLAPP-EASTHAM "BOSTON KEY" on a grey marble base in nice condition. I think the larger flat knob was changed out for the dual layer knob. Makes a nice looking key and works great.
Here is a key from pre-WW1 time called the Marconi "Road Map" key due to the metal connection from the rear terminal to the front contacts. It is an American Marconi key and has a good feel to it, works great. Interesting to note the flat sides of the lever at the fulcrum vs the new Bencher straight key of today with similar fulcrum design, also a great key.
This photo shows the KW Auxillary Hand Sending Key 500 cycles made for Navy Department (BU.SE) by Marconi Wirless Telegraph Co. of America RFG No.NSA 750, Cont. No.2411, Date 1917, Type CM425, Serial no. 570, AC Volts 250, AC Amps 20.
Here is the photo of a Bowman spark key made for Sears, and others back then. A nice working complete spark key on gray marble base. No markings by Bowman company.