Hello. It is only one set, not two, if that is what you mean.

One pair is included in the delivery.

It is one set consisting of left and right rail , so two rails total.It's not made for being use on both side.

According to our supplier : It is one set consisting of left and right rail, so two rails total.

That seems to be exactly what is implied. Unfortunately, I found nothing at the manufacturer's site. But other sites always sell these things in pairs.