At the same time, in the early 1990s, mailboxes began to be installed in groups in Finland. Boxes lined up, side by side significantly accelerated mail delivery instead of individually installed mailboxes and door delivery. People who worked in banks started asking if they could get a mailbox version of the return boxes. When the request was repeated several times, Lasse, who oversaw sales, suggested to his brother Martti that he would also design and manufacture mailboxes.

The mailbox had to be stylish and functional and withstand Finnish weather conditions from rain to frost. It was also essential to comply with the strict regulations required by Finland’s postal office on the size of the mail slot and mailbox. Bobi's functionality was finally tested in practice at Posti's headquarters when a brick-sized phone book was pushed through Bobi's mail slot. The phone book slipped into the box and the development work was sealed when Finland’s Posti approved Bobi. In use, it was also noted that the curved shape was not only beautiful and classic, but also suitable for Scandinavian conditions. The curved top of the mailbox did not collect water or snow but effectively drained them. The mail remained dry.