I may be a little late on this one, but what?
According to Magpul, the belts are crafted from a combination of inch-and-a-half wide top grade bullhide leather and, staying true to the Magpul-ness, reinforced polymer and is rigid enough to carry a holster but comfortable enough for normal, regular belt use.
The polymer supposedly prevents the belt and its holes from stretching which, honestly, would be quite nice… but not at a $84.95 USD price point. With the Canadian dollar as low as it is that puts this belt, at the time of this post, at about $113 due to the exchange rate alone. For a belt. At that price I would expect it to not only hold up my pants but to pull them up after I’m done on the john, too.