Carbine Doncaster Vestibule Set L1 Lever SetCarbine 7000 Series Doncaster Vestibule L1 Lever Set Standard 70mm Backset. Function Outside: opened by key only. The outside lever always remains rigid Inside: opened by lever at all times Optional choice of a standard or clutching function, the clutching model features an operation where the outside handle still moves when locked, ideally to prevent lever damage from forced entry Additional Information L1 lever design compliant with BCA codes and