Which Vortex flash suppressor should I use on a OA 98 .223

From what I've been told, Vortex seems to be the best non-thread flash suppressor out there for a OA 98 in .223 (clamp-on vs. threaded barrel). Could someone PLEASE tell me where to find the correct size of the non-thread type for a OA 98. Also, if there is something better out there that is made for the OA 98, let me know that too.ThanksCraig