The KHS31 headset is very comfortable and can be adjusted to fit your ear size. With PTT microphone, the KHS-31 is very functional and offers superb sound quality. For use with TK3230K,TK2400 Series, TK3400U4P, TK3402U16P. Headset Type: Monaural; Headset Style: Over The Ear; Earpiece Type: Earloop; Earpiece Material: Rubber.