I tried two styles of ant moats. This one is best: a choice of colors, transparent enough to see the fill level, simple design that actually works. Ants must cross the water to get to the feeder hooked below, and the span of water is too large for ants to span it. An unexpected result: birds use these as water sources, perching on the rim and dipping for a drink.

I needed another ant moat for my Baltimore Oriel feeder, since the one I had finally fell too much and couldn't hold water. I didn't really want clear, since that is what I had, and didn't want a solid container, since it was high up and couldn't tell when it needed more water. So when I saw this, it fit the bill, including a nice looking hook bit. It looks sharp above my feeder, and so far is doing what it is suppposed to do--keeping away ants! And it isn't too small either--was worried about that. Holds about 3/4-1 cup water. Which means I don't have to fill it all the time.