It's great Carl !!!
after starting, just turn the dial, Select between 4 fixed points. Not sure of the psi numbers, but there are pictures that show the type of use. (It basically changes the engine speed for more pressure)
I use lowest pressure setting with a foam cannon to wash my truck ..... (Yes I said foam cannon)..no damage at all !!!
very handy to go from that to a wooden fence, then to concrete
it really handles all the jobs well !