History

• Tefillin are a pair of black boxes worn by Jews on the arms and forehead. In English, they are termed "phylacteries." These boxes are often made of kosher leather or animal skins. Black straps, which are also made of leather, are attached to these boxes. Tefillin are worn every weekday during morning prayers. Tefillin worn on the hand are called shel yad, while those worn on the forehead are called shel rosh.
  
  

Peshutim

• One of the four types of tefillin is the Peshutim (Simple Ones). This type of tefillin is made with several pieces of parchment that are glued together within the slit square to divide it into the required four compartments. The parchments are used to form the inner walls of the shel rosh or head tefillin. Parchments must be glued correctly; otherwise the tefillin will not be kosher for use.
  
  

Peshutim Mehudarim

• The second type of tefillin is called the Peshutim Mehudarim (Superior Simple Ones). The boxes of this type of tefillin are made from a single piece of parchment or leather and are created as 32 mm boxes only. Usually, goat skin is used in making this type. The actual look of the Peshutim Mehudarim, however, resembles that of tefillin made from cowhide, although not as durable.
  
  

Dakkot

• Dakkot tefillin (Thin Ones) are those made with a thin layer of parchment stretched over a structural base similar to that of the Peshutim. The entire box of the tefillin as well as the inner and outer walls and base are formed by this outer parchment. The design makes the tefillin halachically acceptable or acceptable by Jewish Law; however, because of its thinness the tefillin may also easily become invalid, particularly when knocked. Normal wear and tear can also reduce its halachical desirability.
  
  

Gassot

• Gassot (Thick Ones) tefillin are made from a single thin piece of parchment or leather. Inserts are often used to make sure they close flat. Production of these tefillin require an arduous and complex process, and several tons of pressure in industrial presses are often required. The resulting Batim or boxes are extremely durable. To make this type of tefillin, cowhide has to be chosen properly and carefully. Usually, leather from the cheeks and neck of the animal are used because it is in these areas that cowhide is thickest.