An arbitrator is a qualified attorney who must meet certain requirements and is trained to be an arbitrator before being assigned to your case.
An arbitrator will gather evidence from both you and your lawyer, listen to your statements, and make a decision. This decision could, or could not, be legally binding.
The arbitrator is a neutral professional and has no financial, official or personal interest in the fee dispute between you and your lawyer.
Most arbitrators are usually lawyers, but there is always one non-lawyer arbitrator on a three-person panel.