The topeak mtx ex beam rack is a composite version of the topeak beam racks it is designed for use with the topeak mtx rear rack bag range and can carry loads up to 15lbs making it ideal for casual tourers or commuters topeak trunk bags slide easily onto the bike rack using topeak39s patented quicktrack system which holds the bag securely and makes it easy to remove the bag and carry it with you if you need to the universal deck design will accept all quicktrack trunk bags it also uses