This single clamp cup is manufactured by Indipets in New Jersey. We include two of them with the airline carrier as the single clamp/screw allows flexibility in placement. The cups are close to the floor and don't have too much space to turn or tip.
Pak-o-Bird made and shipped before 2014 came with two of these cups. By mid 2014, each Pak-o-Bird includes two King's Cages 5 oz. stainless steel cups with the double bolt. It is a patented product with the Quicklock design that prevents the bird from removing the cup from the holder/ring. The double bolt design also avoids the cup from tipping or turning.