64GB SDXC Komputerbay High Speed Class 10 Memory Card 15MB / s Write 20MB / s Write 64 GBRien to say about the writing speed with a 550D L + Raw. By cons very fragile card; the problems start after qqles months by the inability to read the card on the PC (still using USB cable with the device-PC) and then ultimately the card is not recognized either by a PC or device . Unable to retrieve the contents of a data recovery utility; lost photos and HS card.