I called them up and they said that it is made for 5 inch lights... But i have seen people with PIAA 540's on them so i think im going to get the 520's, All pro has their own reccomendations i think they were Soltek lights but they're very expenseve when i looked them up on ebay... now my problem is going to be wiring the lights... I want to set them up on a Factory switch too, but im going to have to reasearch alot to do that one.