I got this 16GB Class 10 micro SD. It was described as up to 20MB per sec but it was only 6.51MB per sec [large Files].
I made a mistake by not reading the reviews. the seller wud always make the item sound good but its the customer review that is more reliable
I copied 1GB [265 mp3 files] to the memory card, it took 3:10 [3 mins 10 seconds] the speed was 5.26MB per sec.
It shud have been at least 10MB per sec.
I had no problem recording video on my phone.
It is VERY SLOW compared to 20MB per sec
Always read the reviews before you buy no matter how good the shop or company is.