The RAF later developed their own beam guidance techniques, such as GEE and Oboe. These systems could provide an accuracy of about 100 yards radius, and were supplemented by the downward-looking radar system H2S. The British development of specialist 'Earthquake' bombs (which needed to be dropped very accurately) led to the development of supporting aiming techniques such as SABS and the Pathfinder Force. Specialist units such as 617 squadron were able to use these and other techniques to achieve remarkable precision, such as the bombing of the Michelin factory at Clermont-Ferrand in France, where they were required to destroy the workshops but leave the canteen next to them standing.