The Ernie Ball Expression Overdrive is a unique take on an overdrive. Instead of on or off, you can slowly blend in the amount of overdrive you want.
The overdrive itself is transparent and nice-sounding. It also has a tone control and up to 5-6dB of boost (I’ve seen two different reports on the boost volume).
Guitar is Squier CV Starcaster
Amp is Strymon Iridium, Round, B