Com systems for camera operators have historically been expensive and cumbersome. Often over $1000 for just a two user starter system. And I’ve even tried “walkie talkies” to no great success. You need full duplex, among other things.
Seems the folks at Eartec are changing this paradigm. I’ve not yet had personal experience with these, and it almost seems too good to be true. Once you shoot with a full duplex com, you will find it hard to do without.