Gordon, the class rating denotes the write speed. A class 2 2 mbps, class 4 4 mbps etc. The highest rating for SDHC is class 10. John. ----- Original Message ----- From: Gordon Atkinson To: Access-UK Sent: Monday, April 01, 2013 3:08 PM Subject: [access-uk] Memory Cards Hi Folks, I am looking to buying some extra memory cards for the Milestone 312. I had a look on Amazon but find the various numbers confusing; for example: SanDisk SDSDB-032G-B35 32GB Class 4 SDHC Memory Card I am familiar with the gigabyte and high capacity but not the class numbers. I would be grateful if anyone could explain the various options. It might be better to write to me off list. Many thanks. Gordon Atkinson ** To leave the list, click on the immediately-following link:- ** [mailto:access-uk-request@xxxxxxxxxxxxx?subject=unsubscribe] ** If this link doesn't work then send a message to: ** access-uk-request@xxxxxxxxxxxxx ** and in the Subject line type ** unsubscribe ** For other list commands such as vacation mode, click on the ** immediately-following link:- ** [mailto:access-uk-request@xxxxxxxxxxxxx?subject=faq] ** or send a message, to ** access-uk-request@xxxxxxxxxxxxx with the Subject:- faq