(Simcro) Designed with a unique bottle attaching washer to prevent vaccine leakage. Bottles attach easily and are protected by a secure collar. Barrel orientation can be adjusted to keep bottle upright and maximize user comfort. Metal luer lock tip makes needle changing easy. 2 ml adjusts from 0.3 ml to 2 ml in 0.1 ml increments and includes collar for 50 ml or 100 ml bottles. 5 ml adjusts from 0.5 ml to 6 ml in 0.5 ml increments and includes collar for 50 ml or 100 ml bottles, plus large collar for 250 ml bottles.