The Berkley® Bio-Dip is an unscented, biodegradable bait dye specifically developed to work on Gulp! and Gulp Alive! baits where others won't. It even works on live bait! Available in primary colors so you can mix and match them to create your own custom color. For best results, pat the bait dry on a paper or cloth towel and dip it into Bio-Dip for an instant color change.