the 4 pack just comes in handy. friends can show up unprepared. the presta valve will work on presta or schraeder rims, and the long stem works in any size rim. a 29er tube will fit into a 29er or a 26 inch rim in a pinch. I like these cause i can get the core out, and add a bit of sealant.
great for riding in the fall weather. the merino wool is warmer and feels warmer. many other arm warmers are a lycra, which will work fine until they get wet, then then stay clammy, and wet. the cutter gun warmers were great on the bike, i have now started using them on trail runs.