Since September 2003, [Crest Aluminum] has been carefully designing a sliding window and door that will put our dealers a cut above the rest. The new Everest Win-Door™ is now allowing our dealers to go toe-to-toe with other industry rivals. With the highest standards in mind, the Everest WIn-Door™ is manufactured with the safety and comfort of 5/8" Tempered Glass with Low-E coating and Argon insulating gas. Flush mounted, finger-operated window handles combined with tandem patio door rollers gliding on a stainless steel track make opening and closing the Everest Win-Door™ almost effortless. With several other features including the "soft slope" sill's rounded surface for ease of cleaning, the Everest Win-Door™ is the window & door system that everyone is asking for!