The older sibling to our best selling 10L mini backpack, the 18L Optimist is roomier, tougher, and ready for even more adventure! An infinitely practical backpack, with a sleek silhouette and exceptionally durable design, it's highly functional with minimal fuss. Made in USA and covered by our Lifetime Warranty. -18L capacity main compartment -Front facing zipper pocket for stashing quick-grab items -Roomy elastic side sleeves for water bottles -YKK® zippers -Durable and lightweight outdoor materials