After careful consideration, and months spent sourcing and testing, we are changing to TPU (Thermoplastic Poly Urethane) as waterproof liner material for all of our bags, and discontinuing the use of PVC.
There are several advantages to using TPU:

TPU is much stronger than PVC at the same weight: it far outperforms on abrasion, puncture and torsion tests

TPU is more resilient, and can theoretically be flexed an infinite number of times without losing structural integrity

As a far less volatile compound, TPU does not leach the environmentally and physiologically damaging chemicals
which PVC does, which means less environmental impact, and greater health safety for everyone working with the material

 

As TPU is a more recently developed and less widely available material than PVC, and therefore significantly more expensive, we do have to change some of our prices. However we are confidant that this is an accurate reflection of the increase in quality and lifespan of the bags. (We still have a few bags made with the PVC available in stock, but will not be making any more.)