Got this to change my EMG-equipped Fender Jazz to volume - blend - master tone. It does this well, but hadn’t realised that I also had to get a new tone pot (active, not passive) to go with. Having done so, it works well, though there isn’t much room for the battery under the metal control plate — you need to remove the under-plate washers from the pots to make it all fit, it’s that tight. I’m very happy with the unit, less so with the installation process and am not looking forward to changing the battery. But no routing required, just about.