Drilling rig? I bet you can use a pipe wrench with a rag wrapped around the filter to keep from scratching it up, unless the only pipe wrenches left on location are a 48" and a 60". Lol. I use to be a rig electrician, and it seemed like the only pipe wrenches that were on the rig were the two big ones.Was wanting to do it before make my roadtrip home from the rigs. Guess it's gonna have to wait because I don't carry any tools on hand to get this thing unscrewed. To bad this thing came so dam tight wanted to look at it. I have about 800 miles on it right now.