Who rings the doorbell of Gregor Samsa's house and how does the narrator describe this character?

When the doorbell rings at Gregor Samsa's house, he answers the door to find a young woman. She is a locksmith who has come to fix the lock on one his home's doors. She is described as being very short, with a back that was "bent forward in a perpetual stoop" (197). Her hair is pulled back with a rubber band to keep it out of her face and she looks to be in her early twenties.