Two-piece bands in rock music are quite rare. Modern bands that use this format include Ninja Sex Party and Death Grips. Other pop bands from the 1980s, who were ostensibly fronted by two performers, such as Wham!, Eurythmics, and Tears for Fears, were not actually two-piece ensembles, because other instrumental musicians were used "behind the scenes" to fill out the sound. Two-member pop music bands such as Soft Cell, Blancmange, and Yazoo used programmed sequencers. Sequencers allowed bands to program some elements of their performance, such as an electronic drum part and a synth bass line. When electronic sequencers became widely available in the 1980s, they made adding in musical elements easier for two-member bands to perform. Rex (until shortly after scoring their UK breakthrough hit, at which point they expanded to a four-piece and more). Other examples of two-member bands are MGMT, WZRD, Pet Shop Boys, Hella, Flight of the Conchords, the Ting Tings, Hall & Oates, They Might Be Giants (from 1982 to 1992) and T. In many cases, two-member bands omit a drummer, since guitars, bass guitars, and keyboards can all be used to provide a rhythmic pulse. Two-member rock and pop bands typically omit one of these musical elements. Two-member rock and pop bands (such as The White Stripes, Tenacious D, The Black Keys and Twenty One Pilots) are relatively rare, because of the difficulty in providing all of the musical elements which are part of the rock or pop sound (vocals, chordal accompaniment, bass lines, and percussion or drumming). The Black Keys are a two-part band consisting of drummer and a vocalist/guitarist lineup.