The Do-It injector works, but with extreme pressure to fill a large multi-cavity mold. I am convinced the 1/4" opening in the cap versus 3/8" opening is a major factor in the need for increased pressure required to fill the mold. IN addition the marble size ball on the Do-It injector hurts the palm of your hand when injecting. My new injectors will be here in a couple of weeks. I will let you know how they work.