J-bar
n.— «Install a mechanical device that locks to the steering wheel, column, or brake to prevent the wheel from being turned more than a few degrees. Commonly called clubs, collars or J-bars, these devices can act as a deterrent if installed properly.» —“Deter vehicle theft” by Dan Harvey InsideBayArea.com (Oakland, California) Aug. 2, 2006. (source: Double-Tongued Dictionary)