Win Key Viewer
Win Key Viewer is a freeware program for Windows 10 which shows you your Windows product key and allows you to copy it.
The product key is hidden in the Windows Registry in encoded form. Therefore it is hard to retrieve it without special tools like Win Key Viewer.
option-value.com is a web-based Black Scholes stock option calculator which can calculate the price and the greeks of call and put options.
It also includes the ability to calculate implied volatility.