Pneu-Dart Type ‘U’ disposable Slo-Inject® RDDs are the most versatile and universal tail design for Pneu-Dart Projectors. Aluminum RDDs (3.0cc - 10.0cc) are laser engraved with the volume of the injectable liquids capacity. With this value added feature “at-a-glance” identification will help provide the best treatment possible.Type U RDDs are all equipped with Flight Stabilizers.Pneu-Dart recommends ½" cannula for subcutaneous (Sub Q) injections. This recommendation has been scientifically proven and has been widely endorsed by the veterinarian community. A 1" cannula or larger will yield an intramuscular injection on cattle, cervid and many other animal species.