Multi-effects and tabletop units
Multi-effects like this Boss ME-50 include many effects in one pedal.
A multi-effects device (also called a "multi-FX" device) is a single electronics effects pedal or rackmount device that contains many different electronic effects. Multi-FX devices allow users to "preset" combinations of different effects, allowing musicians quick on-stage access to different effects combinations. Multi-effects units typically have a range of distortion, chorus, flanger, phaser and reverb effects. The most expensive multi-effects units may also have looper functions. Pedal-style multieffects range from fairly inexpensive stompboxes that contain two pedals and a few knobs to control the effects to large, expensive floor units with many pedals and knobs. Rackmounted multieffects units are typically mounted in a rack. Guitarists and bassists may mount their rackmounted multieffects unit in the same rack with their preamplifier and power amplifier.
A tabletop unit is a type of multi-effects device that sits on a desk and is controlled manually. One such example is the Pod guitar amplifier modeler. Digital effects designed for DJs are often sold in tabletop models, so that the units can be placed alongside a DJ mixer, turntables and CD scratching gear. For a DJ, a pedal located on the floor would not be practical because she/he would find it hard to adjust the knobs.