The connection patent
Tefillin by Kesher Tefillin are protected by US patent number US 10,084,581 B2 and Israeli patent number 239014. Kesher Tefillin holds the only existing patent on tefillin – except for HaShem himself! The following drawings will give you an understanding of their complexity. Don’t try it at home, unless you have us with you or your tefillin will not be kosher!