Sorry all for the late reply...I bought one of these from smolt1 on ebay. Within MINUTES of placing my order Bob contacted me via email and sent me the calculator for increased psi, and to let me know my item would be shipping that day. The calculator calculates both pressing weight and psi for all pressing needs. He also sends a booklet which gives this information in abbreviated form to get you started. The press itself is WONDERFUL and really good looking! I keep it out to look at and encourage. The box was well insulated, each piece wrapped to prevent scratching, and the instructions very easy (and I'm not mechanical). Ive made 6 cheeses using this press and its taken my cheese making to the next level. I currently have a cantal pressing at 34 lbs on the pressing arm. That's 7.5 psi/309lbs of pressing wt! Very impressed with this press