A stake bag is one of the smallest items in a UL kit, and Hartford Gear Co's version is built to weigh essentially nothing: 4 g for a small drawstring pouch made from Dyneema Composite Fabric (DCF). DCF is chosen here not for waterproofing in any meaningful sense at this scale, but for its strength-to-weight ratio and resistance to abrasion from sharp stake tips poking through fabric over repeated trips.
The drawstring itself is a hi-vis reflective cord, a small but practical touch for finding a dropped stake bag at a dark campsite with a headlamp. It comes in two sizes: a small 7 × 2.75 inch version sized for compact stakes like the MSR Groundhog Mini, and a larger 9 × 3.5 inch version for standard-length stakes. Each bag is handmade in Hartford, Connecticut, which places it in the small-batch cottage industry segment of UL gear rather than mass production. It is a minor accessory, but one that keeps sharp metal away from the rest of a pack's contents.