Launched in 2010 after five years of research and testing, CND’s Shellac—similar to the gel polish that’s everywhere these days—is perhaps the least invasive version of a UV light-cured, long-lasting lacquer. Unlike with gel, no nail buffing is needed, and the formaldehyde-free range of 30 shades quickly expands with layering to create innovative new hues that will stay mirror-shiny for two weeks. $16