PVA, short of Polyvinyl alcohol filament, can be used either as the main structure or as the support. However, due to its nature of dissolving in water, it is mainly used in printing the support part.
When you build an object that have a lot of hanging parts, you will need some type of support to make sure the entire structure will not collapse before the material have enough time to cool off. In complex designs, it becomes very difficult or even impossible to remove the support parts by hand. This is when PVA material shines. You just have to soak the print into water for a while and all the support part printed with PVA will be gone, left behind your final products clean and neat.
All of our spool of filament come in a vacuum-sealed package that sealed air tight.