The answer given by Tyler C has to be the dimensions of the box, not the product itself, as the product's width and height are industry standards.
Total width of a rack panel is 19.0 inches, give or take. This is not a tightly controlled dimension and so consider that it may be +/- 0.05 inches. Center to center spacing on the holes should be 18.312 inches. The width behind the panel, the part that fits between the rails, can vary quite a bit, but should never exceed 17.70 inches.
Height is "1U" where each "U" is exactly 1.750 inches. However a panel (and any equipment going into a rack) needs to be slightly under that dimension. So calculate your "U" height and subtract about 0.05 inches. Therefore height should be about 1.70 inches.
Depth can be anything. To make an educated guess I measured the width and height of the product in top-down photo and worked out the ratio. Knowing the overall width was 19 inches my calculated depth works out to about 3.6 inches.
These product dimensions could easily fit within Tyler's box. And now I see the Cat 6a panel has a wicked cheap sale price, so I think I'll buy a couple. :-)