About capacity:
64GB = approximately 58GB-60GB
This is calculation difference between manufacturer and your PC, please Google 'USB FIASH DRIVE capacity' to get more information.
Your PC says 1GB = 1.073741824 Billion bytes where Market Defines 1GB = 1.00 Billion bytes.

Note:

Speed based on internal testing. Actual performance may be lower depending on the device, interface, usage conditions and other factors.
1MB=1,000,000 bytes. 1GB=1,000,000,000 bytes. Actual user storage less.
1. Product is 100% authenticity.
2. All products are in line with Sandisk official website.
3. The manufacturer reserves the right to change or modify the product at its sole discretion. Appearance and packaging design are subject to change without notice.
4. Please contact us if you have any questions.

Package

1*SanDisk USB Flash Drive(with retail package)