Not really stiff and thick enough for a normal mid-thickness pile carpet. Might be OK on berber or really short pile. If you have a mid to thick pile carpet get the thicker one. Better than the thinner ones but still not enough.
Moved into new house and needed protection for the carpets. Have used a similar product from Staples before. They will last 2-3 years then start to crack but that is adequate for the price.
Generally adequate features for an economy product. However it breaks apart under the chair casters after a couple years of nearly daily use for a couple hours each.