White lithium grease; does not damage or weaken polymer, extremely visible so you can clearly see your amount and location of lube, not as thin as oil so it doesn't evaporate or burn up, but not as thick as other gun greases so the level of reduces friction provides is perfect. Also since it is white you can see it turn gray from powder residue and carbon and can easily clean and re-apply, but it holds dirt well and still lubricates good when dirty. I will continue using for all of my guns. AK, mosin, 1911, Walther PPQ, ruger 10/22 etc.