What is the R-value of your radiant barrier?

Radiant barrier on its own has NO R-value; it works to block radiant heat (97%) coming in to the attic by stapling it to the rafters, but it has no R-value. Read: R-value and radiant barriers.
Other products try to claim R-value on their packaging, but they are often not realistic values and under perform in most installations. Read: False R-value claims by Other Products.