Serena syringe with two indistinctly adjustable channels or to fixed dosages. Possibility of fixed dosage: -1° channel 2 cc, 2° channel 2 cc -1° channel 2 cc, 2° channel 1 cc -1° channel 0,5 cc, 2° channel 2 cc Charging system through needles and connector tubes from the bottle. Luer Lock attachment. Ergonomic and balanced. Less stress to the animal. It gives a better antibody response with the simultaneous use of two vaccines.