Purinox produced this line of premium bombas for Meta Mate. It’s a unique line in that they are fused using electric pulses and heat as opposed to standard soldering with lead or silver (which releases Cadmium into the product).
All soldering work is done with 340 inox so that the straw does not need washing in sulphuric acid afterward (which is necessary when working with silver soldering.
The bombas are heavier than traditional bombas. It’s the result of the tubes being thicker to resist the uniquely crafted filter pieces.