Only with the advent of modern machinery were the battim machirs (battim makers) able to work with the thick leather which is used in battim. This leather comes from the neck of the cow which is the thickest part. Was the reaction positive towards this new innovation? One of my customers told me that when the first Belzer Rebbe, known as the Sar Sholom was shown a pair of gassos, his reaction was :
“behold, these are the tefillin of the awesome ruler of the world הן תפילין דמרי עלמה”
So even though these battim were most definitely an innovation, they were one which has clearly added many benefits. The most obvious one is that a set of gassos is often a lifetime investment, not a purchase which will last for five or ten years.
I am so convinced of the quality of the beautiful gassos that I sell that I give a lifetime warranty with them. Call me up so we can talk about what set would be right for you.