Due to the discomfort of this angle for the left hand, a new grip was created- traditional grip. In the past, snares were typically carried with slings. Marching snare drums have high-tension heads that manufacturers typically make out of Kevlar or PET film. Sometimes, due to the charts set by the marching band's show, the front ensemble may have a certain position on the field in order to create a certain visual effect. In other cases, marching units may place the pit in the back or behind the band because the band may be too small for them to station the pit in the front. In modern marching band and drum corps- snares, tenors, bass drums, and sometimes cymbals march on the field and are generally referred to as the battery, while the pit (or front ensemble) is stationary in the front of the field. Marching steel pans are rarely part of drumlines due to issues with volume and durability. A relatively small number of bands, mostly at the college level, continue to field such traditional marching keyboard instruments however, most bands have phased out their use. In the past, marching timpani were common before the adoption of the front ensemble, as were marching keyboard percussion instruments such as glockenspiels and xylophones. The battery usually consists of snare drums, bass drums, tenor drums, and cymbals. The battery is the drum section that marches on the field as a group. Drumlines use the term "battery" to refer to a specific part of the drumline.