Heavy duty sealer/varnish for after decoupage?

Question:What is the best sealer/varnish to use on a decoupaged coffee table? I am going to use mod podge to glue the paper but I need a water-based, clear varnish (non-yellowing) to create a heavy, durable top coat. Any good suggestions? Thanks...

Answers:
minwax makes a urethane called "PolyAcylic" which is a water based urethane, ALL water based urethane's DO NOT yellow only the oil based ones so you can use any brand you'd like, I personally don't like to use minwax products cause it's just not as good as it used to be, Good luck Les the painter