These Accessories Also Fit to The Following Systems: Carrera GO!!! Records exactly (1/100 sec.) the times Can be used with all current Carrera racing track product lines Adjustable width continuously to suit various track width For two lane operation Cars are recognized via infrared light barrier Time trials from 1 seconds to 99 min. Lap races from 1 to 999 laps Start phase with acoustic starting lights False start function Battery-operated, 4 batteries AA/LR6 (batteries not included)