BOSS FS-5L latch-type footswitch, MOD version. The "MOD" isn't anything too drastic; it's just that changing the battery was a hassle, so I had a shop modify it to accept a 9V DC cable. This allows for direct power supply from a power supply unit, making it convenient for use on a pedalboard. Due to this MOD, it cannot be used with batteries. I mainly used it for channel switching on my amp, turning the amp's reverb on/off, and turning tremolo on/off. Thank you.