The optional Yapalong 4000 open mic Airtube Mic II headset and lapel microphone. Flexible air tube earpiece. Dual-pin audio plug - 3.5 and 2.5 mm stereo (two prongs). A college field hockey umpire said, "I tried both headsets and prefer the airtube piece over the other one because it fits my ear better. It is less cumbersome, stays in the ear better, and more comfortable. The only con is that you do lose a little bit of sound level, but you can turn the volume up on the radios so it's not a big deal." SHIPPING: 4-6 business days, via UPS Ground