This place is amazing. I don't know whether or not they are over priced, based on a previous…read morereview, but they do have a wide range of antiques: maps, globes, compasses, and feather pens.
The shop was established in 1881 and Francesco, who was very kind and helpful to us, is the 4th generation owner -- a very long ancestry is rooted in this establishment. The service was impeccable and Francesco was very informative and knowledgeable about the history of all the products.
Most of the souvenir items such as pens and journals are located on the ground floor, but the basement has the most interesting items: authentic antique paintings, globes and maps.
I would definitely recommend stopping by the shop when you're visiting Milan.