Must be a list 1a or 1b tyre. List 1a is basically road tyres, Toyo T1Rs, Eagle F1s etc. The AD08s that I have are pretty much at the top of this bracket. Bizarrely, the Hankook RS2 is not listed.
1b covers high performance and R compound tyres, so things like Michelin Pilot Sport Cups, R888s, AO48s etc etc. Slicks are excluded.
I can technically run either, however some events have supplimentary regulations saying that my class must only use 1a tyres, hence the choice of AD08s at the moment.