A needle-less injector suitable for injecting fluid through a surface includes a housing, a driver, an engine and a trigger. The housing contains a fluid and the engine contains a compressed gas. Upon application of sufficient force to the trigger, the compressed gas is released from the engine forcing the driver through the interior of the housing, expelling the liquid from the housing at a speed sufficient to pierce an injection surface. In one embodiment, the needle-less injector includes a mechanism for mitigating the kickback associated with releasing compressed gas from the engine. In another embodiment, the housing includes finger rests that provide stability and resistance to activate the device. In another embodiment, the engine is fitted with a reusable valve. In another embodiment, a safety clamp is included on the housing, preventing accidental activation of the device.