A needle syringe has a plunger and a needle for filling and dispensing liquid from the cavity. The cavity has finger clip with movable locking pins. The plunger has at least one set of grooves corresponding to a specific dosage for the needle syringe, the specific dosage of the groove being demarked by a marking ledge that indicates a change to a deeper depth section of the groove. The locking pins are configured to rest in the at least one set of grooves, such that when the plunger is removed, the locking pins pass within a first shallow section of the groove, pass over the ledge, and continue to pass in the deeper depth section of the groove. When the plunger is depressed in a first partial dispensing movement, the locking pins pass in the deeper depth section of the groove until the plunger depression is temporarily locked when the locking pins reach the ledge, where the dose remaining in the cavity is the specific dosage.