Use the LTH-blanks since it was the first with 2x speed. Later with 4x and 6x speed now. So far, no problems with my Plextor PX-B940SA. As a player I use the Philips BDP7500. Even so never gabs problems. Therefore full purchase recommendation for LTH blanks for this device combination. This may occur when other devices of course again look different, therefore: try only with a small amount!