The ClearSounds ClearLink CL002 Dual Silhouette Hook works with a variety of cellular, cordless and corded telephones equipped with a standard 2.5 mm telephone headset jack. Plug the ClearLink single silhouette hook into your device of choice. Position the silhouette along side your hearing aid or cochlear implant processor. Switch the hearing instrument to “T” or “MT” position to activate the telecoil. Adjust the device's volume and hear what speech and sound should really be like.