Columbia Sportswear Celilo Daypack (Deep Purple). Were constantly testing our products in the worst conditions all around the world to make our products perform even better. Explore how we test, and share your toughest moments of testing here. The Celilo Daypack has 16.2L (989 cubic inches stow capacity, stow away trekking pole holders, and removable waist belt. Patented Omni-Shield delivers protection from outdoors where you least expect it bu.