Collapsible steering columns are required in all NASCAR Cup, Busch and NASCAR Truck Series chassis. They are not only a safety feature, but an excellent way to eliminate flex and binds in your steering shaft. length is measured from the end of the housing to the beginning of the collapsible shaft, there is 8" of collapsibility. The 18" model #SWE405-10001 works well in all short track stock cars.Pit Stop USA offers Sweet 18" Collapsible Steering Column 405-10001 at low everyday prices. Be sure to check out all of our products from Sweet Manufacturing including Sweet Manufacturing Steering Columns and Sweet Manufacturing Steering Columns and Shafts.