Seems like expiration = 2/1/2028 minimum. #3 and #4 specifically. https://smallbusiness.chron.com/check-patent-expires-30481.html Also, https://www.stopfakes.gov/article?id=How-Long-Does-Patent-Trademark-or-Copyright-Protection-Last http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.htm&r=7&f=G&l=50&d=PTXT&p=1&S1=7941822&OS=7941822 http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.htm&r=0&f=S&l=50&d=PTXT&RS=chanbond&Refine=Refine+Search&Query=7941822