You should use what the track provides, and save 50.00. There is no use of buying one when your local track provide them for everyone to use. When you buy a transponder, you also need to charge it. Sometime they will require you to run a different number etc. Bolink distibuted AMB, but bolink no longer distibute them. Here is AMB phone number. You can call them up or Google-it.
http://www.bolink.com/amb.html