Just a heads up if you've never adjusted an i2 valve before. Only adjust the down speed if it's moving, on the buffers, or ball valve closed and man lowering open. Theirs more too it like half turn adjustments only but I'm not the guy to give that information cuz im just guessing off what ive been told. A guy who knows a lot about the dover valves is linden elevator. He's got a website and that's the # frome the site 1-208-754-4884