Best Match US $ 1.76 /piece US $ 2.34 /piece US $ 5.87 /piece US $ 5.60 /piece US $ 3.50 /piece US $ 14.50 /piece US $ 1.50 /piece US $ 63.00 /piece 1.Capacity 16GB = approximately 14GB-15GB 32GB = approximately 28GB-30GB 64GB = approximately 58GB-60GB 128GB = approximately 119GB-120GB 256GB = approximately 224GB-240GB This is calculation difference between manufacturer and your PC, please Google ‘Memory card capacity’ to get more information. Your PC says 1GB = 1.073741824 Billion bytes where Market Defines 1 GB = 1.00 Billion bytes.The pursuit of the perfect person is not recommended to buy. 2.Speed Test (1).The speed show on our link is test by Sandisk/Samsung or by our professional instrument, you’d better use 3.0 interface and 3.0 card reader, then you can get a nice speed. (2).Speed is influenced by many different factors, interface, computer condition , test software,systems,use, etc . (3). Under normal circumstances, due to computer configuration, USB interface, card reader interface, card socket interface and other factors, it will affect the reading speed of the product, the good configured computer can reach 60-90% speed (for example, 100M can reach 60-90M) , but the computer with poor computer configuration can only reach 10-30% speed (for example, 100M can only reach 10-30M), it depends on the configuration of your device. (4).We can 100% promise that our product are all 100% original, there is a security verification label on each package. (5). Once you place your order, it mean you had read and agree with my description. 3. Package If you choose the Accessories (Card Reader/ USB Adapter/ SSD Adapter/other), The number of Accessories is just 1, if you want more Accessories, you can buy another on my store.