Mainline Tru Colours Powdered Dyes, Not a lot we can say about dyes, is there? If we could get them in feed inducing format we would, but we can't! Mainline offer the highest quality powder dyes available, genuine value for money products - a little goes a long, long way. Used in the food industry they have remarkable resilience and stability, and they can be mixed together for a variety of colour permutations in finished bait.