Hi there and welcome
The unit can connect with any headphones, so the choice is very large. When you say best headphones, you need to asses which elements are the most important. Quality is of course important, but for the transceiver there is no point paying $300 for headphones designed for the low and high treble and bass of music. What your really looking for is very good quality headphone that are comfortable to wear. Its comfort that in my opinion is the most important when using a transceiver as you can be wearing the headphones for very extended amounts of time.
With this in mind, I recommend the Sennheiser HD 201 Lightweight Over Ear Headphones
Weight is important to comfort and these are one of the most lightest over hear headphones, you get a 9.8 ft tangle resistant cable, they have a lot of cushioning and very good quality (Sennheiser being a market leader in Audio).
More so, they are very well priced. I really advise on these and you can purchase them via my link below
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If you would like any additional information or assistance, please do not hesitate to let me know.
Else if you can take a second to rate my service by clicking one of the stars at the top of the screen then submit, that would be greatly appreciated.