Carbine Doncaster Vestibule Lever SetCarbine 7000 Series Doncaster Vestibule 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 Fire rated for 4 hours to Tyco specifications