Check water level on new battery! And screw-on lids??

That split ring is the maximum fill indicator, if you fill so the water just comes to the bottom of it, you will see the water form an eye shape. There is ample room above that level and the slots prevent capture that might cause venting out of the caps. This has been common knowledge for about a century, but the advent of “maintenance free” batteries left many with no clue about how things were done.