The Artist Series Synthetic Marimba with the Endurance Field Frame are designed for all outdoor applications. On and off the field, these instruments expand the available octave range beyond 4.3 octaves with a choice of 4.6 octaves or 5.0 octaves The Endurance frame comes standard equipped with the Voyager height-adjustable system, 4 large 8" pneumatic wheels handle rough terrain, and an oversized frame post adds stability.