I use this type of MMC card for my Nokia 6630 and 6680 I work, some applications still do not exist for current smartphones. These cards range from 256 MB to 2 GB. The Nokia 6630 and 6680 have very low memory capacity if not ridiculous, compared to mobile today. Therefore it is best to have at least 1 GB cards, although the increase in memory slowed more or less using the mobile. These cards are easy to handle because they are bigger than SD cards. They can be formatted and you can also give them a name, which is useful if like me has several. They all come with an adapter, which allows you to play on any card reader and on computers with multi-card reader. In summary, MMC memory cards are easy to handle and use. I use since 1999, and I've never had problems reading, recording, data loss or other. So I can say that they are robust and reliable in all tests!