Built for emergency service environments, this adapter, with the push-to-talk amplifier, lets you use any H-series headset top in 6-wire controller and dispatch operation. SHS 1890 with its Quick Disconnect connection allows the use of any Plantronics headset, each with an acoustic limiter, frequency range of 300 to 3300 Hz and less than 5 percent distortion. It features lockable-non-lockable push-to-talk switch and 25" (7,5m) coiled cable.