Memory card is very common useful device; it’s a storage system, commonly memory card used in consumer electronics such as pda, digital cameras, MP3 players, mobile phones, laptop, handy cam, game console printer and other small portable devices, Today in market we have found different type of memory card, like SD,M2, MINI SD CARD,MICRO SD CARD, SD card is second generation Multimedia Card. They are physically the same as an MMC, M2 Memory Stick Duo and Memory Stick Pro Duo are approx. both are similar version. It’s mostly preferred by SONY? Clash of memory card. It’s a very important point to purchase a memory card . because data transfer rate depend on it . How to identify the clash of memory card ? When you purchase any memory card please check on memory card body mention a digit in one round cercal like 2, 4, 6, 8 etc. I have details the below table Class 2 :- you can use for Standard-definition video recording, general stills photography in compact cameras because its maximum data transfer rate is 2 mbps Class 4:-you can use for HD video recording, continuous stills photography in compact cameras. Its maximum data transfer rate is 4mbps Class 6:- Full 1080p video recording, continuous and regular stills photography, its provide maximum data transfer rate is 6mbps Class 10:- Full 1080p video recording, in professional camcorder, or continuous high-resolution stills in SLRs maximum data transfer rate is 10mbps .