OPI GelColor OPI Ink. OPI introduces the latest advancement in the increasingly popular gel service category: GelColor. Each coat cures in 30 seconds and features a custom brush for fast, polish-on application. The 100% color gel formula wears like a gel and looks and feels like nail lacquer that lasts up to two weeks without losing shine. Fully cures from foundation to finish in only 4 minutes and removes with ease. .5 oz.