The IIIf was made with two types of flash synchronization adjusters. The earlier one was had the delay numbers (milliseconds?) printed in black ink, the later ones were in red ink. A table provided information to match up electronic flash or particular types of flash bulbs to a specific delay. I think the numbers were actually different between the two dial types requiring two separate tables. The later red dial models were also divided between those with self-timers and those without.
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