Low rings 4.02 oz.
Medium rings 5.02 oz.
I just weighed them.
For a pair. I've attached weighing photos of a 4KHM ring -- 1052 grains or 2.4 ounces -- and a 5KHM ring -- 1190 grains or 2.7 ounces. 5.1 ounces for the pair. A pair of standard rings doesn't weigh anywhere near 8 ounces.