... .Roller :anti-noise nylon roller ,reduce friction with ground.Lock system :1.multi cross shafts,using solid core square steel ... system :while close the box , automatic locking system will lock the box immediately .3.Automatic re-locking function, when the ... opened by improper way or force ,box will re-lock itself.4.Password lock ,mechanical lock ,which is drill-proof ,smash-proof ,technically open ...