Vintage Speedex Model 450 Practice Code Set. Use as is as a code key, or hook a battery to it and fool around with the buzzer (they can be pesky) or hook up the solid state module I include, that works off a simple 9 volt battery! Rare item from Speedex, collectors item???. Seems like the base is BROWN BAKELITE, Made in San Francisco! Not sure how old but at least 70 years old, I suspect.