Serfas Backlit Combo Cable LockShed some light on the situation. The Serfas Backlit Combination Lock lights up numbers so you can easily operate this combo lock, even when it is dark outside. The thick steel cable and 15mm thick lock keep your bike from being a target for would be bike thieves.Features4 digit resettable combination lockThick twisted steel, rubber coated cableCoiledVinyl coated for frame protectionIncludes bracket and replaceable battery