[M] Silicon Power Elite 256GB Class 10 A1 UHS-I U1 microSDXC Card Review
 

The Elite A1 256GB card from Silicon Power does offer a notable improvement in terms of writes versus the non-A1 variant we have tested before, while offering the same levels of protection against water, dust, high-temperatures, and X-rays. The 256GB of data should be enough for a large range of applications, while the recorded write speeds are considerably higher than the A1 UHS-I U1 standard is mentioning.

http://www.madshrimps.be/articles/article/1001414/