Five-inch version of Versatrig.
Custom made by Hemmi for Frederick Post and Hughes-Owens; no Hemmi model number exists for this model.
I can find no Frederick Post, Teledyne-Post or Hughes-Owens catalog that lists this slide rule. None. Most specimens have date code "SF" (June 1968). Jodie S Hobson has one with date code "SA;" Warren Salomon owns a"TE" (May 1969) Hughes-Owens Pocket Versatrig.
Post model 1451 Versatrig Date code "SF" (June 1968)