The Sennheiser IE PRO Mono Cable is compatible with the IE 100 PRO, IE 400 PRO and IE 500 PRO in-ear monitors. It is a durable, lightweight mono cable that allows you to use just one of the Sennheiser in-ear monitoring headphone earpieces. This is great for when a more balanced listening experience is required. For example, as a singer, you may need to listen to other band members whilst still having a clear audio feed to a backing-track or your own vocal output. On the other hand, a drummer may have a pre-recorded rhythmic clicking sound or metronome playing through their in-ear monitor. The IE PRO Mono Cable allows you to do just that when combined with a compatible Sennheiser IE PRO system (excluding the IE 40 PRO). This mono cable further utilises a comfortable, secure ear hook and reliable connection.