Two boxes. One is the rail system...I have been back and forth with the supplier and retrax about the inordinate amount of leakage..their answer has been this is common if the ramboxes are even slightly out of spec, I can expect leakage and the rails won't sit flush and tight, they refuse to say the product doesn't work as advertised and won't honor the warranty as I am just under a year. The supplier won't honor a return because retrax has not deemed the cover defective.. I have been fighting back and forth with them and have escalated up to the ceo...waiting to see what happens....my advice, is get something else. You don't want to have the issues I am and not have them honor the warranty. The ramboxes seem to present a challenge...I have been looking at the gator and they claim the fit is redesigned to not interfere with the ram boxes...I will do more research before I buy it though after this debacle