A compact and lightweight tracking puck developed by HTC, used to bring real-world objects into virtual reality. It attaches to accessories, props, or body parts, allowing for full-body tracking or custom VR peripherals within compatible VR systems like the Valve Index.
Valve Index with Vive 3.9 trackers VR chat with mods near Scion on Twitter if you want help.
""The speaker explicitly mentions 'Valve Index with Vive 3.9 trackers' as part of a VR setup, indicating specific VR hardware accessories. 'Vive 3.9' is likely a slight misremembering of 'Vive 3.0' or a general reference to the series."