Gassot, dakot or peshutim tefillin: what are the differences and which to choose?

Tefillin must be perfectly square (ribua), the head box made from a single piece of leather (including its four compartments), black, and stitched with sinews of a kosher animal. A box that loses its square shape or whose paint chips can render the tefillin pasul even if the parchments are perfect.

Gassot ("thick") are made from a whole cowhide, soaked, pressed in moulds under several tonnes and dried for months. The result is a dense block of leather that a craftsman (batim macher) carves and sands to a perfect square.

Advantages: a lifespan of decades, corners that can be corrected, renewable paint. It is the only type we recommend for a bar mitzvah.

Peshutim mehudarim are also made from a single piece of leather, but thin, folded to form the compartments. They meet the single-piece requirement and are kosher. Their fragility (rounding corners, difficult repair) makes them a solution for a limited budget or a second travel pair, not for a lifetime.

Not to be confused with ordinary "peshutim", assembled from several glued pieces of leather: many authorities consider them pasul. Beth Hasofer does not sell them.

Gassot: thick leather, one piece, 40+ years, repairable, €890 to €1,490. Peshutim mehudarim: thin leather, one piece, 10 to 15 years, hard to repair, about €490. Dakot: thin leather on a base, one piece, medium durability, rare. Ordinary peshutim: several glued pieces, disputed kashrut, not sold.