Batman has many tools to get around, but when he's on foot, and he can't glide to where he needs to go? He busts out his grappling gun.
This tool has taken many looks over the years, but, the purpose has always been the same, get Batman from one building to the next. Or, get him out of harms way. The grappling gun is able to bear Batman's weight, and sometimes' the weight of others, and then pull them to where it has latched. Batman often has more than one in his belt, and has used multiples at the same time to perform various feats.