Probably 30 wasps between the two jars.
Wasps fly into the kiddie pool to collect water to build their nests. I sit nearby with my jar. If you move smooth and quick you can catch them before they take off. Then they just fly to the top of the container. I sit the container upside down on the surface of the water between wasps. The limit comes around 15 in one container because then they start to knock each other out of the air into the water where they can try to swim to escape.