Excellent speed!
This one is the original Sandisk Ultra.
Don’t buy the white ones, as they are slow and aren’t featured on the Sandisk website.
When used with the adaptor which is provided it pushes out superb speed even when used with high end DSLR’s like Canon 5D mark 3.
In case of rooted mobile this micro sd card pumps out enough speed to use the card as game storage space and render games directly from it and that too without any lag.
Buy only if you have a decent to high specification smartphone or to use as a option with any DSLR otherwise you can use a class 6 or class 8 micro sd card for slower devices like Moto G 2-3 or similar.
A 100% worth purchase.