So I was wondering how someone would go about determining whether his tefillin was Peshutim Mehudarim, Dakos, or Gassos, or even Gassos Prudos? Can this be done without taking the tefillin apart?

  • 1
    Probably an X-ray, MRI or something like that could figure it out.
    – Double AA
    Feb 2, 2016 at 4:11
  • Related judaism.stackexchange.com/q/67914/5275
    – DanF
    Feb 2, 2016 at 14:23
  • 2
    @DoubleAA I'd like to see you try walking into a hospital with a pair of Tefillin and convince the staff to give them an MRI.
    – DonielF
    Jul 5, 2017 at 18:27
  • @DonielF If I offered enough money they'd probably let me. Plus there are MRIs in university research labs too that might be less busy.
    – Double AA
    Jul 5, 2017 at 18:30

1 Answer 1


An experienced sofer stam (scribe) or batim macher (maker of tfilin boxes) will often look at them and tell you in three seconds, out of experience dealing with hundreds of tfilin over their life.

The main difference between gassot, dakot and pshutim is the type and thickness of leather. This is difficult for a non-professional to assess. However, very often, pshutim tfilin will have other shortcuts which are easier to assess (e.g., base not parallel with the top of the tfilin, shape not exactly square, carton boxes around the batim instead of more sturdier plastic protectors).

A great place for tfilin-related content is the International Stam Forum - a discussion forum for sofrim which has excellent content. I have asked your question to its moderator, R Eli Gutnick from Melbourne and here is is response

The easiest way to tell is by weight. Pshutim are made of very thin‎ hide. Traditional Dakkos are a bit more substantial, and gassos are made of very thick hide, and consequently are heavier.

When someone brings me their tefillin to check, I can usually tell if they are gassos or not as soon as they hand me their tefillin bag, just from the weight.

Besides for the weight, looking side on through the Mabarta‎h (back part of the tefillin box where the strap goes through) is another way to tell. The thickness of the hide will be clearly visible. Pshutim will be about half a millimeter thick. Dakkos will be noticable thicker. Gassos will be much thicker.

Another way to tell is to ‎look at the underside of the tefillin. Gassos will have a charitz (groove) for the stitches to sit in. Pshutim and dakkos usually don't have this groove, and the stitching is raised above the hide.

With regards to ‎prudos, the easiest and least invasive way to tell if the four batim of the shel rosh are separate is to see if they move. This can be done by gripping two adjacent batim and pulling them (hard) away from each other. If one observes a little bit of movement on the top charitz (groove) between the batim, this is usually indicative of prudos. If they were glued, they wouldn't budge, no matter how hard you pulled.

Here's a photo showing the difference between the mabartah of older tefillin peshutim and gasot.

Peshutim on left, gassot on right

  • @EzraHoerster :->, but I really meant to write "assess" as in "easier to evaluate". Or did I miss another one?
    – mbloch
    Feb 2, 2016 at 15:58
  • @EzraHoerster also I should have said it but the most important thing in tfilin is the yirat shamayim (fear of Heaven) of the scribe, then comes the quality of the parchments and the batim. Do not worry if you have dakot, but maybe when you have a chance you will get them checked and maybe maybe one day you will upgrade them. I received pshutim for my bar mitsva and bH upgraded them over time as I learned more
    – mbloch
    Feb 2, 2016 at 16:00
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    OK I understand what you were trying to say now. Thanks for the clear up. As for the grade of my tefillin, I am completely unconcerned.
    – ezra
    Feb 2, 2016 at 19:28

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