2-pack or 2K is an epoxy-type varnish/hardener coating.
https://www.eastwood.com/1k-coating-vs-2k-coatings
I use a spray gun, if I’m doing a significant amount of painting, if not, I use Dulux duraMax for general hard-wearing coat, but any 2k/2-pack aerosol can does the same job.
I like it because it is interior/exterior, non-yellowing, and you can coat everything from paper to wood to metal.