Do tzitzit need a hechsher (rabbinical supervision) to be kosher?
Recently I received an inquiry from a Jew in Istanbul asking about the rabbinical supervision on the tallit katan and tzitzit products we sell.
Which rabbinical authority are you supervised by? For example, when you buy a mezuzah or a pair of tefillin,
don't you make sure first that the sofer is a trusted individual...