Hi
If you are looking for a bobbing holder that should never fail you, try a Matarelli. They are made out of stainless steel with brass buttons for the spool.
Very old design and now classed as a classic compared to the more modern stuff (TMC ceramic and Rite bobbins etc). The great thing about the Matarelli bobbins is that if you dop it on a hard floor, 1, They never break, 2, If they get a burr on the end of the tube, it is an easy job to reectify this with a small piece of leather and either very fine valve grinding paste or Brasso, you rotate the end of the tube on the rough side of the leather with the abrasive paste, a few minutes later, as good as new.
They are not as fancy as the TMC in looks but I have had a bunch of them for up to 20 years, great product.
I had a brief period when I bought the white TMC bobbins, but after a disaster with a white TMC bobbin that broke when I dropped it on the floor (I was really P***** off). I would not buy a bobbin holder with a full length tube again. I suppose thay were never designed to bounce back onto the table unharmed but things do fall on the floor.
To date, my Matarelli bobbins have never let me down, great product but old school now I suppose.
Good luck with your new bobbin holder.
Kev.