What does '1 Gallon Combined' mean - do I get a gallon of each part?

"Combined" is the total amount of epoxy you get once the resin and hardener are mixed together. Every kit includes both parts, and the size you select is split between them. It is not that amount of each part.

UltraClear Bar & Table Top Epoxy and UltraClear Art & Craft Epoxy mix 1:1, so the split is even. 1 Quart Combined is 1 pint of resin and 1 pint of hardener, and it is the smallest kit we offer. 1 Gallon Combined is 1/2 gallon of resin and 1/2 gallon of hardener, which makes 1 gallon of epoxy when mixed. 2 Gallons Combined is 1 gallon of resin and 1 gallon of hardener. 3 Gallons Combined is 1.5 gallons of each, and so on. On the Bar & Table Top Epoxy page, sizes run from 1 Quart Combined up to 60 Gallons Combined.

If you want a full gallon of resin plus a full gallon of hardener, order 2 Gallons Combined. For 3 gallons of each part, order 6 Gallons Combined.

The mix ratio is still 1:1 by volume, equal parts resin and hardener, which is why the kit is split evenly. "Epoxy" refers to the finished product; the resin and hardener are the two components you mix to create it, and the combined size measures that finished amount.

UltraClear Deep Pour Epoxy mixes 2:1, so its kit is split differently: a 1.5 Gallon kit contains 1 gallon of resin and 1/2 gallon of hardener.