One of the earliest effects pedals was the honorable DOD 250/MXR Distortion+, and while revolutionary at the time, it was due for an overhaul. Too shrill, too quiet, inflexible- all issues solved by the OD250 while delivering a familiar gritty hard clipping overdrive and distortion. Important additions include the Tone control, Clipping switch, and + (more gain) switch. Where the original got harsher as the gain was turned up and there was no way to adjust the treble content, now there is a simple tone control to shape the top end from biting to super smooth. a 3-way clipping switch allows you to adjust how much compression happens in the second gain stage. The + switch kicks up the gain and body. A little boost, a lot of compression, some gritty overdrive, it is all possible with the OD252.