This is a nice studio and good for one person (the bathroom is separate). The flat has all basic amenities for cooking and washing, and a wardrobe with hangers.
The location is great to walk around the city and reach the main touristic spots and museums. It is also very close to Atocha if you wish to take an intercity or regional train.
Marta is a great host, and has been very responsive to any issues or queries.