Arc'teryx Aperture Chalk Bag - Large Imported Snap closure 4" high 10" wide APERTURE CHALK BAG - Twist closure chalkbag, the bag opens and closes with a twisting motion that seals chalk inside and shrinks the volume for easy transport. ALPINISM & CLIMBING - Climbing equipment designed for efficient movement and protection in alpine environments SYNTHETIC FIBRE - Engineered materials that offer enhanced properties or performance.