FX USA recommends Super Lube part number 92003 for use on all o rings in my FX impact X. I know this because I called them the guy went out to the technicians desk and picked up the bottle he was using to rebuild guns and told me the part number.
If anybody is using Super Lube there are many different types of Super Lube you must use part number 92003 silicone lubricating Grease. NOT the multi-purpose Synthetic Grease. And Super Lube Dielectric grease is slightly different as well.