Selected international designers, illustrators and artists are regularly invited to submit designs for this one inch (25mm) button badge series. B.I.O. (By Invitation Only) Series used to be an infrequent event but in 2012 the B.I.O. Series 12 release finally caught up with the years. Since then B.I.O. badges are released annually with B.I.O. Series 18 due in 2018, etc.