Allflex Draw Off Injector/Drench Syringe has adjustable dosage from 1 mL to 20 mL. It has a 20 mL automatic self-filling rear tube that is designed to be used as an injector or drencher . It has a double O-ring piston and metal and durable plastic design.. It has easy V-grip for high-volume use and easy to adjust handle tension for improved performance. It has easy-to-clean external valves and removable piston shaft. It has amber-colored barrel that reduces UV exposure.