*Package Include: Choose "8GB":1PCS*64GB Usb Flash Drive Choose "16GB":1PCS*64GB Usb Flash Drive Choose "32GB":1PCS*64GB Usb Flash Drive Choose "64GB":1PCS*64GB Usb Flash Drive Choose "128GB":1PCS*128GB Usb Flash Drive Choose "256GB":1PCS*256GB Usb Flash Drive Choose "256GB(pack of 2)":2PCS*256GB Usb Flash Drive Interface, USB Interface, without driver, plug-in and play, hot plug-in Compatible with PC, Notebook, MAC Support Windows 7/8/10,Windows Vista,Windows 2000,Mac OS X,Linux. Data: Data shall be retained for 10 years at further More than 1000000 times to wipe number: erasable The Self - protection: zero track protection, automatic antivirus Flash memory vendors are using decimal arithmetic: 1MB = 1000KB, 1G = 1000MB calculated, but the operating system is using binary arithmetic: 1MB = 1024KB, 1GB = 1024MB. so there are some differences between display capacity and nominal capacity of flash memory products.However, this is allowed to exist. Please do not doubt his authenticity. About capacity: 8GB=approximately 6.9GB-7.3GB 16GB=approximately 14GB-15GB 32GB=approximately 28GB-30GB 64GB=approximately 59GB-62GB 128GB=approximately 118GB-124GB Refund&Change Policy: *If any defect happen within 5 Years,plese tell us,we will ship new one for FREE! *30 Days no reason to Refund!You never have to worry.