Trolley rod, roller how to choose

Buy PC trolley case, there are three important considerations, rod, roller, zipper.
Rod material is usually aluminum alloy, steel, the structure has a cut-off, two cut-off, three cut-off. Two cut-off, three cut-off, is the rod can be adjusted according to the weight of the box length. Optional, the rod must be selected built-in and steel or aluminum, aluminum light and strong, otherwise barbarous handling can not barbaric, in addition, take a look at other configurations of the PC trolley case, such as the retractable button set whether the human nature In the pull rod is smooth and so on.
Roller material is usually rubber, wear-resistant shock absorption, noise. It has built-in, there are external. External wheels, which can roll in any direction, are often called "caster wheels." The benefits of "Caster" is that the PC trolley case can change its direction as your body moves freely, but its drawback is that it can not withstand the harsh loading and unloading when checked. To be on the safe side, the built-in rollers are safer, though they can not change direction at will.
Zipper zipper in the smooth fit without stuck, is an important indicator of consideration. However, larger zippers generally give a more secure feel.