Patent 7428770 was granted and assigned to Termax Corporation on September, 2008 by the United States Patent and Trademark Office.
A spring fastener, which comprises two engagement springs in opposite sides of the fastener. Each engagement spring has an engagement portion comprising a hindrance portion, which increases considerably the removal to insertion force ratio as compared to such ratio when the engagement portion does not have the hindrance portion, thus permitting very easy insertion into, with considerably more difficult removal of the fastener from the slot of a panel.