This high-speed storage device features a reversible USB Type-C connector for simple data transfers between smartphones, tablets and computers. Performance levels reach up to 150MB/s, enabling rapid movement of large media files and documents. Note that available storage capacity may differ from stated hardware specifications due to calculation method variations between manufacturers and operating systems.

SanDisk OTG USB3.1 Type c Flash Drive Mini U Disk 150M/s
About capacity:
32GB = approximately 28GB-30GB

64GB = approximately 58GB-60GB

128GB = approximately 114GB-120GB

256GB = approximately 224GB-240GB

512GB = approximately 460GB-476GB

This is calculation difference between manufacturer and your PC, please Google ‘usb flash drive capacity’ to get more information.

Your PC says 1GB = 1.073741824 Billion bytes where Market Defines 1GB = 1.00 Billion bytes.