The manual http://www.tigersunited.com/resources/wsm/wsmN27.asp Actually says "not more than 5 amps". As I recall, I found a different online resource that had the 3.5 amp number but I can't find it right now. The current spec for the two horns is the same as far as I know. Driving them from a relay makes all the difference in the world when they're in the car... Theo