They sell it direct:
https://www.everbritecoatings.com/cart/protectaclear-coating-only-c-7.htmlI got a quart and a spray. I like 2-3 applications of the spray better. It applies a thinner coat. You have to babysit the liquid because gravity will cause it to pool. Just dab with a paper towel every 10 minutes or so. Doable, but kind of a pain. When applying over patinas (like vinegar/salt), the spray works great, but the thicker liquid may blister and peel.
I think there's a manual device you can use to spray the liquid by blowing. I'd love to find out more because the spray can is more expensive.
By the way, if you ever have any questions before or after purchase, the lady who answers the phone is VERY helpful. It's worth buying just because of the customer service she provides!