I have the one on the left. It's for DCs, Calibers, and also the Maverick, I believe. It works just fine with my Mark III, and has for years. It's still just a footswitch. However, the light lies to you: it's lit when you're on rhythm and off when you're on the lead channel. "Fixing" it would require breaking and moving exactly one solder joint, but I'm too lazy. :lol: