Nylon is certainly stronger...and more expensive than Polyethelene (also known as Poly).
Net strength is measured as tensile strength. Tensile strength is the measure of 1 single strand of material that is stretched vertically and then measured digitally to the point that the strand snaps.
So, for example, if you are considering purchasing one of our #36 heavier duty nets, one single strand of this material will break when 320 lbs of resistance is applied to it....as opposed to our standard #21 net which will break when 220 lbs of resistance is applied.
How does this affect you? The heavier the net, the more useful years you may get from your batting cage (and this will vary by amount of use, climate and whether you take your net during an off season...especially you live in a colder northern climate.
Longest Lasting...more money - for pro quality!