128 vs. 123 gb Cruzer Blade


I just bought a 128 gb Sandisk Cruzer Blade (2.0), and compared it to another 128 gb Sandisk Cruzer Blade (2.0) that I’ve had for a couple of years. My OS (Linux Mint) says the new one is only 123 gb. The older one is 128 gb. The packaging is also different (but it’s been a couple of years), but the flash drives look identical on the outside. The difference in capacity suggests probably at least one of them is fake, maybe both. I wanted to ask how I can go about identifying them, or if the numbers are enogh.

Thank you ,