Thank you for bringing this to our attention! We appreciate your feedback about Rust-Oleum Varathane Stain and Polyurethane. If wanting to protect an outdoor wood surface, the use of a spar urethane is recommended. Rust-Oleum Varthane Spar Urethanes are available as a water-based or oil-base that offers different finishes that can be used outdoors over Rust-Oleum Varathane stains!
http://www.homedepot.com/s/varathane%2520spar?NCNI-5&style=List&s_tnt=82648:1:0