This appears to be a REI Half Dome backpack, specifically in a red and black color scheme. The text on the bag clearly identifies the brand "REI" and the model name "Half Dome". The Half Dome line, while highly regarded, has had its backpack models discontinued and primarily exists as a popular line of REI tents today.
Features
Color: The backpack is primarily red and black with some gray accents.
Material: It is likely made from a durable nylon material, suitable for hiking and camping use.
Design: The visible section shows mesh back paneling for ventilation and padded shoulder straps for comfort, common features for day packs. It also includes a sternum strap and a waist strap for stability.
Pockets: This model generally features multiple pockets for organization.
Sells typically in the range of $15 to $50. Local pickup in Denver area and cash only