Abstract: A method and apparatus for adjusting the contents of a needle-less injector that contains an injectable product are described. A needle-less injector includes an adjustment switch in mechanical contact with the driver of a needle-less injector. A user may displace the adjustment switch to expel air or gas contained in the product section of the needle-less injector prior to administration of a needle-less injection with the same. The adjustment switch may alternatively or additionally be used to expel at least a portion of the injectable product contained in the needle-less injector to reduce the volume of the product to be injected with the needle-less injector.