Toronto. When I was a kid, I saw small ads in the American photography magazines of the day for a Kalart rangefinder to bolt on to a press camera. The strange name caught my eye.
This particular ad is for a Kalart flash bulb synchronizer gadget that custom-attaches to a Graflex to permit use of shutter speeds above 1/500th (up to?) second with bulbs. George Dunbar came across this novel war time ad in the March 1944 issue of Popular Photography.
The arrangement uses the focal plane shutter and must be factory installed. As far as I know, the only bulbs that worked with focal plane shutters at all speeds were the FP bulbs.