Cat's Sneeze recommends

The MoonCup Menstrual Cup - economic, completely healthy and non-toxic, practical and comfortable to use. A wonderful option as a feminine hygiene product, the MoonCup is also environmentally friendly.

More information in English here:

http://www.mooncup-info.com/

and in Finnish here:

http://www.kuukuppi.fi/index.php?main_page=page_2&language=fi

You can also purchase the product from the link above.

This is also a useful link if you need more info:

http://kuukuppikunta.net/