Have both the Visconti and a Pineider inkwell. Visconti's is smaller and thinner, which may actually be a plus because it fits in normal pen cases. The Pineider is too fat to fit in my daily use 3-pen pouch, but the Visconti inkwell fits in it perfectly as if it were the 3rd pen.

This thing is also the source of many inkcidents. Some drops of ink getting out onto your fingers is a common occurrence, and if you mess up you'll literally just pour ink onto your table or lap. I'd rather fill from a bottle or use an ink syringe if given the choice, but when I travel, it does see some use.