That's a slot. Split rings look like the attached pictures of a 6 lug wheel.
Attachments
Split Ring 01.jpg (75.98 KB, 168 downloads)
Split Ring 02.jpg (87.66 KB, 168 downloads)

Last edited by buoymaker; 07/26/2022 6:08 PM.

"Adding CFM to a truck will only help at engine speeds you don't want to use."
"I found there was nothing to gain beyond 400 CFM."