Does absolutely nothing
I was replacing my well used nail block, and this looked like something that would do the job. I was excited about it’s delivery, as my old block had been reduced to shreds from use after approx a year. I mistakenly assumed this would be a great replacement, equating cost with quality, which was dumb, I admit.  Wrong.  The product arrived and I eagerly went to work, using the quick short brushes back and forth across the nail, as I was accustomed to doing.  No change. Tried again - nothing. I would have been better off waving my hands in the air. I’m stuck with a whole bag of these useless things, but maybe if I glue them to a brick, I could use them as a doorstop.
Rating: 1 stars