The aerospace industry has for a considerable period of time adopted rigid borescopes as the preferred choice of instrument for the inspection of aero gas turbine engines. Olympus have partnered with many of the principal engine manufacturers to produce a range of dedicated aeroengine borescopes, designed and built to meet the engine manufacturers' specifications for optimum inspection performance. Some of these instruments feature a rotating graticule to aid in the visual assessment of defects, and others have a removable handle for areas where access is limited.