you referring to the circled number at the top right hand corner of the card itself? i just now noticed it after reading this, lol. idk what it means but mine is a 2 and works in my BB Bold. just go to your cell service provider store and buy one from there. i'm sure they wouldn't sell you a micro sd card that wouldn't work in their phones.

i got someone at work who used to work for sandisk, i'll try to ask him and see. but if anybody knows, i'd like to know too