This is another member of the Average Dice family.
No frame needed this time.
You have to make the average of the 3 visible faces of the tetrahedron to find the result of this D4.
For instance, if those faces are numbered 1, 7 and -2, as 1+7-2=6 and 6/3=2, the result would be 2.
More informations
in this post.