[M] Toshiba EXCERIA M303 MicroSDXC Card Review
 

The new EXCERIA M303 microSDXC cards from Toshiba are aimed towards 4K or Full-HD content recording and can fit the smallest available devices; these are rated as having V30 Video Speed Class and from our tests, we got near 70MB/s writes, which should be enough for most multimedia content.

http://www.madshrimps.be/articles/article/1001091/