What's this on the Quest 2 controller? It looks like a speaker. : r/OculusQuest
Amazon.com: Controller Cover Compatible for Oculus/Meta Quest 2, Anti-Bumping Silicone Soft Ring Cover with Quest 2 Controller Protection.(1 pairs, 2 colors) : Video Games
Amazon.com: KIWI design Halo Controller Protector Compatible with Quest 2 Accessories, Anti-Bumping Silicone Ring Cover with Protection : Video Games
Sony's PSVR2 teardowns reveal how the headset tracks the Sense controllers - The Verge