SNS is a brand name . Many, many other brands do the same system with very little variance in the technology between them. Nail Alliance do it for their brands (Gelish, Artistic, Entity). Pretty sure most wholesalers do it too (e.g. Sallys/Salon Services).
I use Venus nail supplies they are a london, uk based Vietnamese nail supplier but i have found them to be extremely reliable and very helpful also they stock most of there 400 + colours so great choice xx been using them 4 years