1200-denier heavy-duty polyester. Dimensions: 12" x 18" x 11". Large 27L main compartment with dedicated 15" laptop sleeve and tablet sleeve. Rain Defender® durable water repellent (DWR) keeps your gear dry in light rain. Contour fit shoulder straps. Padded air mesh back panel. Reinforced Duravax™ base panel. Large main compartment. Zip organizer pocket.