Salsa EXP Series Saguaro Seat Bag - Medium GraySalsa EXP Saguaro Seat Bag Black Medium. Where tight trails and rugged terrain would batter other bags the EXP Series Saguaro Seat Bag shines. It connects to saddle rails at four points for supreme stability (say goodbye to sway). Its modular dry bag holster design makes loading and unloading a cinch and ensures your gear stays as dry as when you packed it. A purge valve lets air out but not in so you can compress the bag to pack more. The holster