this one's free take out the turn signal bulbs on the front. The relay will double in speed and can be seen from the back
hes basically saying its like when ur front blinker goes out, the back ones flash fast, as for doing it the way these other guys are saying, id go with that.
if u do the one l.e.d. in the front and the stock in the back it sould do the same. that and u will have it flashin from and back. thats how i have it on my bike...