Product review (2 stars): Is It Really Alkaline Resistant?
The tape came and the package was written in all Chinese except for a few phrases. One of which said "Drywall Joint Tape". The description of the product on Amazon says this should be alkaline resistant, which is needed to tape cement board.  The package in no way eluded to this characteristic.  The fact it came straight from China (though they do their best to make it look like it came from the US) makes me concerned this stuff will be eaten up by the alkaline in the thinset on the cement board.  This stuff will work for drywall no doubt but for cement board you might want to look elsewhere (or trust the description on Amazon and risk your tile job falling apart).