should be a 906 flasher BUT 5v
Thanks Chuck for catching it
http://cointaker.com/products/5v-flasher-spike-system-wedge
Make sure when ordering, that it's the 906. 906 is the "wedge" or "bayonet" style end. Meaning it can just be pushed into the socket.
The 89 flasher is the same flasher, but has the twist in end.