I was reading the description of the SanDisk 128GB Extreme microSDXC UHS-I Memory Card. The specs were what I wanted. The speed was what I wanted. But my device supports only cards up to 64 GB so I selected the 64GB size. BUT... When I got the item I saw the speed was slower than I expected. I checked the description before returning it and saw that the specs for the 64GB card are lower/slower than the 128GB card, even though they are both the SanDisk Extreme microSDXC UHS-I Memory Card. I guess the moral is to read the full description after you select a different size/capacity of a given item.