I got mine at
www.customdynamics.com. They have the bulbs for about $62, and they also have splice-in modules for about half that. The splice-in units are at
http://www.customdynamics.com/signal_dynamics_back_off_brake_light_modulator.htm. I have bulbs on my Bonneville and America, and I have the splice-in Wig-Wag unit on my Trophy. All things considered, I prefer the splice-in versions. Installation is easy.
