Rock Tips Liquid Callus Formula

However I gotta admit that I rarely use it.
Actually I've mostly used it to strengthen my nails (I'm not a flat-picker) however ordinary nail polish is better for that purpose.
But it works well as fingertip protection and I use it for "backup" purposes. Though, I suppose it might be really useful if you haven't played for a while.

pros: saves your fingertips
cons: a bit less fingertip feeling

I found this formula very handy and easily applicable. Stays on for two - three days. Really helps me play longer and do slides without getting string burns and "slots" on my fingertips. Also helps you build calluses over time. Really good for bass playing as well as guitar. I will get more when I'm out.