The Station is a piece of hardware. The Pod is the part that does the work, and it is the part you replace. That split is deliberate, and it is worth understanding because it determines what this costs you over time.
The Station is built to be kept
Stations are made from durable polypropylene and designed for season-after-season use. There is no filter to replace, no cartridge, no power supply and nothing to plug in. You buy them once.
The Pod is the consumable
One Pod treats one Station for about 30 days. It breaks down and slowly releases plant-derived clove and garlic oil actives into the Station water. When it is spent, you replace it — and that is the whole of the ongoing cost.
Buy the Stations once. After that, the only thing you are buying is Pods.
What a season looks like
A six-Station yard uses six Pods a month. A 12-Pack covers about two months; a 20-Pack covers most of a typical season for a smaller setup, and gets the lowest cost per Pod. Working the maths before the season starts is usually cheaper than buying 4-Packs reactively in August.
It also means the decision you are making at the start is mostly about coverage, not commitment. Getting the Station count right for your yard matters more than which refill pack you begin with, because the Stations are the part you keep.