SD Ultra: UHS-1, minimum read speed 10MB/s, max 80MB/s
SD Extreme: UHS-3, minimum read speed 30MB/s, max 90MB/s
SD Extreme PRO: UHS-3, minimum read speed 30MB/s, max 95MB/s
http://kb.sandisk.com/app/answers/detail/a_id/1996/~/difference-between-speed-class,-uhs-speed-class,-and-speed-ratings...