Physically, the MPX100 is a 1U?high, 2?in, 2?out effects processor based on 240 presets that can be edited on a fairly basic, but nevertheless useful level. The analogue I/O is on unbalanced jacks, with a high?impedance input that will accept electric guitars as well as regular line sources. For practice purposes, the left output jack doubles as a phones output, though it's not very powerful.