CIPA 36501 Camlock Base Auto Dimming Rearview Mirror with Compass, Temperature and Map Light Add the convenience of auto dimming to reduce glare from headlight of vehicles approaching from behind Installation is easy  attaches to existing mount (new mount spring also included) Dual map lights provide downward illumination that won't interfere with driver's vision Features a digital compass, temperature readout, and dual map lights "Ice Warning" flashes when outside temperature drops below freezing