The sidewinder is a lightweight expandable spinner luggage with built-in 3 digit combination tsa approved locks. it is made from a polycarbonate composite and utilizes a zipper closure system. polycarbonate is the same material used in the making of bullet-proof glass. it is both durable and flexible so that when under stress, it flexes to absorb an impact and then flexes back to its original shape. the sidewinder utilizes spinner wheels that are specially made in japan. these wheels allow for such fluid motion, that it will seem the luggage is gliding on its own power. the innovative trolley handle system allows for flat packing, as the tubes are incased in a special protrusion of the outer shell so that the tubes do not interfere with the packing on the inside of the luggage. the sidewinder includes built-in 3 digit combination tsa approved locks on each piece. these unique locks only allow certified tsa officials to open, inspect and re-lock your luggage if necessary. 7 year worldwide better life warranty. customer service phone number 866-439-7872.