Keyguard for the Surface Go 2 keyboard model 1840.  This keyboard is sold under different part names in different colors.

The default material is 3/16" clear acrylic.  1/8" high-impact PMMA is available for users who require the openings to be shallower, but is not recommended, since it is more flexible and may become warped or dislodged. There are also a number of 1/4" thick materials available.

No attachment method is provided with this keyguard.  You'll need to attach it yourself with something like double-sided tape, Velcro, or mounting putty (Blu Tack, etc.)