The Reflex brand is well known in the heating industry and across europe as a leader in pressure control heating technology.
These expansion vessels are nitrogen filled, which have a big advantage over the standard compressed air, as the oxygen in compressed air permeates through the membrane, reducing the pre charge pressure. Oxygen can also oxidize the membrane causing under inflation and deterioration of the membrane. Where as the Nitrogen version prolongs vessel pressure for longer and will not cause corrosion. All this maintains and extends the pressure and vessel life for longer.