Gewa Micro Teflon

I have mid or low priced guitars with no locking tuners, and always had at least some issues with tuning stability, especially on stratocaster type guitar with floating tremolo. I used to use graphite from pencils, and it helped a bit, but I always wanted to try some teflon-type lubricant.
Gewa Micro Teflon is not expensive, and it does it's job really well. Of course, when you get a small tube like this (4 grams), you tend to think at first it will not last a long time, but the truth is that it will. You need only small "blobs" of teflon on nuts/saddles.
It's a good product, helps with tuning, but it is not a magic trick that will solve all of your problems. You need to stretch new strings, learn to make adjustments on guitar and (if you can or want) invest in better aftermarket parts for your guitar. But every little thing helps, and as far as this product goes, I like it very much.

Great lubricant for your strings so they don’t catch on the nut. I use this stuff on my Squier Classic Vibe strat and my PRS SE Custom 24. If you’re like me and you use the whammy bar a lot, you NEED something like this at your disposal. It improves the tuning stability A LOT.

I use this stuff when I restring my guitars. Just dab a small blob (smallest amount possible) into the nut slots. I also use some on the string tree. Don’t put too much on, you’re only wasting it.

The downside is that you have the squeeze the bottle quite hard to get some out, even a small blob, so be careful. Also when the bottle is getting empty, the plastic bottle can split and it will leak. This happened to me recently, but I just put some tape around the bottle to seal the split.