2004 GMC Envoy Owner's Manual - Page 115

Rear Storage Area Rear Compartment Storage Panel/Cover Your vehicle may have this feature. This shelf position is used as a cargo shade. Insert the front corners of the panel into the top guides and slide the panel forward. Press down on the back of the panel to lock it in place. {CAUTION: If you were to carry things on the adjustable panel when it is in the upper (cargo cover) position, then during a sudden vehicle movement or a crash those things could be thrown around in the vehicle. You or others could be injured. When it is in the upper position, always secure any cargo on the floor beneath the panel/cover. Upper Position 2-49