My advice is don't waste your money on one! I see far too many people that have them and it makes little to no difference. Remember a radar detector only picks up the radio waves sent out by police radar units which are bouncing off other vehicles, which are always the larger and closest target. So in simple terms, the Officer must leave the radar unit on, and almost all police radars have a on/off button, which means your radar detector won't know what is going on until it's too late. And let's not even discuss getting around the laser! Just some friendly advice from someone who knows;-)
