All race vehicles will be required to have transponders for 2018. The required transponder is the RACEceiver LAP-ALT-100 LapCeiver Audible Lap Timer, which is $159.99 and can be purchased at Speedway Motors
https://www.speedwaymotors.com/RACEceiver-LAP-ALT-100-LapCeiver-Audible-Lap-Timer,93694.html