On the Missouri Quilt Company video, she is using a half hex ruler:
https://www.youtube.com/watch?v=1Dn_4vTxwfk
The company sells the half hex ruler in two different sizes. Maybe one of them is yours? Doesn't really look like the binding tool, though.
https://www.missouriquiltco.com/shop...half+hex+ruler
Edit:
And here is a link to the video where Jenny uses the binding tool (2.5" wide) to make a friendship braid:
https://www.youtube.com/watch?v=EpHAp_pyVXQ