Diving Regulators are the life support equipment involved in Diving.
Their purpose is to provide air to the diver at exactly the same pressure as the water, in order for us to breathe. The technology is fairly simple and the designs haven’t been changed in years.
A top of the line Regulator would be one that has a diaphragm first stage and a balanced second stage.
Medium range, would involve a balanced piston system with either a balanced or unbalanced second stage and Entry Level is an unbalanced piston first stage with an unbalanced second stage.
Don’t fall for the marketing reading a regulator – the basics are: is it balanced or unbalanced and does it have metal internal parts.