This British Military Rucksack is 16" tall, but extends to 25" with its internal bellow. The rear pocket is 13" x 10" x 4" and the side pockets are 9" x 6" x 3" (more than enough room for your Sigg bottle, stove or canteens). It's a great ultralight backpacking rucksack, with a light alloy frame to create a nice airspace for comfort and better weight distribution. Total volume is 2100 cu/in up to 2800 cu/in with inner sleeve extended.