TW-25B, on all of my rifles especially my AR's. It was good enough to keep my mini-guns running in A-stan, as well as my rifle there, and works awesome stateside. I live and hunt in southwest Nebraska where it is hot, dry and dusty in the summer, and winter temps often fall well below 0. Never had a f to f due to lube issues with it. I still bring it with me to the qual range every range year, and use it on my weapon their, and on my younger soldiers weapons when they have issues, and hopefully before an incompetent RO gives their rifle the squirt gun CLP bath....