I don't even know what to do with the reply to this post. Please do not go view that link for more information on the cleats - that is not a reputable retailer by any means.
The tag indicates that the particular pair of cleats is a promo sample. This usually indicates a pair of shoes that was made in some small amount in a different run than a production run. This is a pair of cleats released as a marketing effort for Nike's Super Bowl 50 collection, and my guess is that this pair ended up being sold at a Nike outlet once the marketing effort passed and they went unused. In this case, I believe the cleat had an actual retail release, at least according to a Nike News release prior to Super Bowl 50.
The short version of that is that the cleats are authentic and safe to use for athletic activity, they were likely just made at a separate point than the pair that was sold on the Nike website.
The cleats are plastic - they have a metallic paint coating on them to give them a chrome aesthetic.