Good quality for price. Adjustment is proper and precise. Knob turns 360 closing halfway. IDK about material, but there is mild magnetic reaction!?! From center only see pic. That is a Quarter and penny. The magnet is high quality neodymium. There is look of brass when closed. Time will tell craftsmanship, can't beat cost. Works perfectly for my setup. I have an aquarium and aquaponic setup. I don't know the PSI. Strangely Packed better than my lucky from diff store.