Retevis RT-6S Walkie Talkie 6W UHF 400-520MHz 16CH CTCSS/DCS with Original Earpiece 2 Way Radio Ham Amateur Radio Transceiver (2 Pack) and Retevis 2 Pin Throat Mic Earpiece Headset PTT (2 Pack) The shell is made of imported PC material,easily respond to salt fog, humidity, high temperatures and harsh environments 16 memory channel,easy to use: each work group can have their own channel to minimize disruptions in other departments Operation is simple and reliable: 1 knob for ON/OFF/Volume control, the other for channel switch; 1 PTT button for speaking The PTT button is nice and soft, and easy to use, which will be good in the cold if your fingers are a bit numb Wider frequency coverage, extends to 520MHz: you can program the frequency you need