PROMASTER VELOCITY CINE MEMORY CARDS acheive incredibe read & writespeeds, especially when used with UHS-II cameras and card readers. Their250MB/s write speed and V90 video speed class mean your camera willnever outpace this card wether you''re shooting ultra high resolutionvideo footage or taking still photos at fast frame rates. Velocity CINEcards are also backward compatible with UHS-I cameras, readers, anddevices so you can be sure to get the highest performance no matter whatyou are using. 2000X 300MB/s Read Speed 250MB/s Write Speed UHS-II Speed class 3, U3 V90 Video speed class UHS-I backward compatible