It's the lamp they most likely put your hands under. The UV light helps to cure and dry the nail polish, I believe they're mostly used for gel based products.

[Look how happy he is when he gets to explain stuff!

He drops couple of the colors back to the crate, leaving him with burgundy, crimson and fire red.] There are more neutral and nude options too, if you feel like these are too much for you. No black, however.