Interestingly, when I first saw these at my Costo, I was wary because they didn't have the thickness printed on the box and it was really hard to find that information online.
So I bought a single box as a test and to my delight, they were as thick as the 6.3 mil (160 micron) gloves I was buying from Amazon, so I went ahead and bought 3 boxes.
This was pre-quarantine, so I wasn't stockpiling or anything, but I was really glad I had them when the Covid situation started.