This is the rocker Style Hazard Switch for Triumph TR250 to TR6 1972, Spitfire 1968 to 1975 and GT6 1968 to 1973. Lucas # 39665. The original switch 148401 (lucas# 35857A) in NLA.  This switch came on the 1972 cars as an upgrade and is a little wider.  Some dash filling will be needed.  Please call for details.