Samsung | SAMSUNG Original USB3.1 Flash Drive FIT Plus 128GB 256GB 512GB 400MB/s High Speed Mini Pen Drive 64GB Read Speed up to 300MB/s

About REAL Capacity64GB = approximately 58GB-60GB128GB = approximately 115GB-120GB256GB = approximately 230GB-240GB512GB = approximately 460GB-480GBThis is calculation difference between manufacturer and your PC, please Google 'Memory card capacity' to get more information.For your referenceYour PC says 1GB = 1.073741824 Billion bytes where Market Defines 1 GB = 1.00 Billion bytes.Speed testing:1) About USB Flash 3.0, please use a USB 3.0 USB Flash Drive to connect a USB 3.0 interface for the H2testw on your PC.About USB Flash 3.1, please use a USB 3.1 USB Flash Drive to connect a USB 3.1 interface for the H2testw on your PC.If you use a USB 2.0 interface the speed will be much slower because:The bandwidth of USB 2.0 is 480 Mb/s, whereas the bandwidth of USB 3.0 is 5 Gb/s.2) Actual speed may vary depending on host device conditions (card reader, adapter, USB port etc.) Write speed will be slightly lower.Please read carefully. Thanks!!!1. All products are 100% authentic, original authorization, general agent direcely supplys.2. The SAMSUNG has three big production sites: China, South Korea, Philippines!All products delivery randomly.