It’s a tiny earpiece with a mic from the 1950s. They’re great for poor communication, missed radio calls, filing ASAPs, and permanently damaging your hearing. Oh and also you get to sound like you’re talking through a 20’ long roll of toilet paper with every bit of background/wind noise on the radio. That will cause ATC to use the phrase “say again” more often than usual and so you’ll press the mic practically inside your mouth to repeat the transmission so that you can make a garbled reply. It’s the clear choice for someone making $300k+ per year.