All materials used are from natural or animal (kosher species) sources including the thread, sinew, ink and glue. Tefillin contain the 4 paragraphs from the Torah which mention the mitzvah of tefillin.
Four paragraphs in the Torah mention the mitzvah of tefillin. These four paragraphs are painstakingly handwritten twice in tefillin, once on a long single strip of klaf, parchment, one column for each paragraph, for the arm tefillin, shel yad, and again on four separate strips of klaf for the head tefillin, shel rosh. There are 3188 letters in tefillin. It takes the sofer, scribe, approximately 10-15 hours to complete a pair of parshios.
Each letter must be written precisely according to halacha, Jewish law, of which there are thousands, and each letter must be written in order. If the sofer, scribe, writes or fixes one letter out of order it would appear kosher but in reality the tefillin or mezuzah is passul, invalid. Similarly, each letter must be formed by writing and not by scratching. If the sofer scratches, even a fine line, completing the form of the letter it would make the letter appear kosher but in actuality the entire Torah, tefillin or mezuzah is passul. Therefore, the sofer must be an expert in thousands of halachos and maintain careful concentration.
Batim are the pair of leather housings which contain the parshios, parchments.
We carry 2 types of batim:
Peshutos: The upper section of these batim are made from one piece of parchment which is cut in a manner so that they can be folded and glued to create solid boxes. Additional pieces may be added to strengthen them. The batim are then set into a base of thin hide. Due to their light weight and thin walls they tend to gradually warp more easily and have a shorter life span.
Gasos: These are made from one solid piece of hide, from the face and neck, from a thick skinned animal such as a bull. Great expertise, time, effort and precision are required. On the one hand they require delicate handiwork while on the other hand they are pressed with many tons of pressure. They take many months to make as they need to dry properly in between each stage, preferably through the Summer and Winter seasons, so they will permanently retain their form. They are far superior both aesthetically, halachically and qualitatively. They last many years and can be repaired and refinished as new. It is worth every effort to acquire gasos.