The Rebbe advises consulting expert scribes for Chabad tefillin details and explains differences in Shimusha Rabba and Raavad tefillin. He acknowledges the prayer request at the Ohel and blesses Yitzchak Leib for his bar mitzvah to grow as a Chassid, yerei Shamayim, and lamdan, encouraging daily Chumash, Tehillim, and Tanya study.
https://www.torahrecordings.com/rebbe/igroskodesh/014/005/5155