Mark up profit or royalty

[Predator3]

High, I am new to the site and looking for advice. I have a product that I purchase from a lab and have been selling it to a small market for a year and a half. I have been approached by several large companies that want to market and sell the product. I have two options first I can sit back let them take care of everything(advertising, manufacturing, selling) and receive a 5% royalty. Second they said I could just supply the product to them with my mark up included and receive no royalty. Lets say the product cost me $6 plus $2 for packaging and shipping. In the second option they are going to pay for all marketing/advertising costs(roughly $250,000) and sell the unit for $20. How much profit should I have in my total price to them.

Thanks