This is the most consistently accurate/well built regulator on the market! it stays on pressure even when your CO2 tank level goes down. UL listed. Approved for use by all major breweries. Shutoff Valve is ball type check valve that prevents product back-up into regulator. Solid brass body. Regulator has "Shut down" safety system (blow off at150 PSI.) Permanent Quad-Ring Seal on inlet nipple helps eliminate a source of leaks. No need to use a new fibre washer each time tank is changed. Heavy duty UL rated dual gauges.