XXL runs extremely small
I'm a Clydesdale, and I bought the XXL size thinking the waist was 42-44 inches.
The waistband, unstretched, is only 16 inches. Stretched to it's limit (which is pretty much un-wearable) it's around 20 inches.
So, word to the wise. Their sizing charts are extremely inaccurate at the upper end of the scale.