The Benelux Mark 12 was Cyclo’s answer to the Simplex Juy 51 and Huret Louison Bobet models. It pandered to a 1950s obsession with giving the rider real-time control of chain tension - an obsession that vapourised as suddenly as it appeared.

• Publisher: Cyclo Gear Company
• Country: UK
• Date: 1957?
• Derailleur brands: Cyclo Gear Company
• Derailleurs: Cyclo Benelux Mark 12