Horweens Zug is respectable but not true to Heather Gorse / Zug as we know it and used on past models (eg: no Swiss chocolate byproduct leftovers added).
If I can find the samples of Horweens Zug, I'll post them here. Otherwise EG Paris has additional samples. Three colors were offered: black / oxblood / dark brown. I think ~2mm thickness.
Zug was the town in Switzerland where the leather was created and now, Zug is just the stamped pattern grain name btw originally known as "Martin's Grain" (no clue who Martin is/was).
There is some interesting history on the forum about the original leather (pg 427 on this thread)......aforementioned was from my memory.
Regardless of leather producer, should still make for a cool boot.
Please see this post:
It is called Martin's grain as it was made by W&J Martin's tannery. Note the names of the variety of leathers they made in that post. Please see a recipe for Zug leather also included with no mention of chocolate syrup. I would be interested to know if there is any real evidence supporting the use of chocolate syrup, I believe it may be a myth.