Marching percussion instruments are specially designed to be played while moving. This is achieved by attaching the drum (s) to a special harness (also called a carrier or rack) worn by the drummer, although not all marching bands use such harnesses and instead use traditional baldrics to sling their drums (the British Armed Forces, for instance, still use the old style of slung drums). The drums are designed and tuned for maximum articulation and projection of sound, as marching activities are almost always outdoors or in large interior spaces. Articulation is paramount to producing a "clean" sound from all the drummers in the line. These instruments are used by marching bands, drum and bugle corps, indoor percussion ensembles, and pipe bands. A marching percussion ensemble is frequently known as a drumline or battery.