It's just called a bezel if I remember correctly. If you're wanting to add it to the Silverado, Tahoe, etc. clusters, I'll save you some time. It doesn't fit.
The needles are too long and the numbers are a little off from the Escalade to the other clusters.
I've tried it on all the clusters because I wanted to see if it would fit, it didn't.
I think the piece individually was about $40