It's great to see the speculations flying about, lol
I have bought a set of 5Zigen Titanium nuts from Envy when I bought my wheels.
- Yes, they are sold as a set of 20 nuts
- Yes, there are 16 regular nuts and 4 locking nuts
- Yes, the key is included and will fit the regular aswell as the locking nuts
- No, the price is not for just 5 nuts
- Yes, I have put leccy tape around my socket to protect my wheels, and also I know that my local tyre fitters actually use a plastic sleeve on their socket to prevent damage too.