This likable, but grubby, catalog shows:

• A couple of eerily happy cyclists on scan 1. He looks as if he cycled straight from the battle of El Alamein.
• The early version of the BSA 4-Star derailleur. This had a simple pulley cage and a rather tidy integral spring design. The later version was crazier on both accounts.
• A price list showing that buying a 4-speed derailleur version of the BSA Golden Flash bicycle costs you a mere £3/6/4 or 14% more than the single speed. That seems rather good value.

• Publisher: BSA
• Country: UK
• Date: January 1950
• Derailleur brands: BSA
• Derailleurs: BSA 4-Star