Another thrift find. Photogenic is still in business since 1903.
A camera flash is a xenon filled bulb that gets a quick burst of power from a capacitor. This allows a very quick and very fast flash for quick photos. The unit pictured is the power supply that can flash the bulb for a photo. The connection to the right of the buttons is the trigger control from the camera or another unit. The connector on the top of the unit (Black grill) connects to the flash bulb on a cable. This unit is often stored under the tripod for the flash. It can output 200 Watt Seconds of light at the color temperature 6500K and 900V DC power. There is also a 200 Watt Second booster you can add. It can output continuous 10 second flashes, or 8 hours of 5 second flashes. Depending on the flash duration it can output 1/1000 of a second to 1/3000 of a second. 1/500 of a second with the optional booster.
If you want to dig deep into the specs, I found the PDF Manual here: https://www.butkus.org/chinon/flashes_meters/photogenic_studiomaster/photogenic_studiomaster_ii/photogenic_studiomaster_ii.htm