The next generation of Rule 1 Protein is here. Pro6 is a blended protein featuring 6 protein sources delivering 25g of protein with only 120 calories per serving. Why would someone want a blended source of protein? To delay digestion and slow release the amino acids into the blood stream over time. Pro6 comes in 3 great flavors. If you're looking for a midday protein or want to boost the protein content of any meal, Rule 1 R1 Pro6 is the go-to.