Based on this question, Shulchan Aruch (O"C 34:2-3) says that only people who are noted for their piety should put on Rabbeinu Tam tefillin. Why do Lubavitcher chasidim (and descendants of certain ...
Mikshah tefillin are tefillin battim which have no filler material in the titurah (base). Why is filler material even necessary? The photo below illustrates the thickness with a piece of filler ...
I sometimes see on the net and in person cases where people wear retzuot which are black on both sides, what is the rationale, if any, for doing so?