Williams Sound NKL 001 Neckloop 18" (Mono Plug), Use with Hearing aids Equipped with a T-Coil Switch or an Induction Earphone, Moderate to Severe Hearing Loss, Adult Size Use with hearing aids equipped with a T-coil switch or an induction earphone For individuals with moderate to severe hearing loss Recommended for FM receivers and select IR receivers Moderate to severe hearing loss, Adult size, Integrated safety breakaway device 18" Cord length, 3.5mm monoaural plug, Impedance 8-16 ohm