On any trip underground you're almost guaranteed to ruin one piece of gear or clothing. It's a tough environment, and as such it requires unusually tough gear. The Swaygo is one of the toughest tools I own. The minimalist roll-top bag is made entirely out of polyurethane impregnated and coated nylon, that is tough as nails (and closer to a car tire than anything else I can think of). It has RF welded seams, and the roll-top is locked by a carabiner (unlike a previous bag I used that had plastic clips that failed mid-trip). The roll-top combined with the impregnated nylon makes the bag waterproof, and the toughness of the skin means that even in scrapes and falls the gear inside is kept safe and sound.