Adrenaclick and generic versions of it. It's not a direct substitute, it can't be dispensed to fill an Epipen prescription, but it is the same drug, the same dose, and for the same purpose (emergency administration of epinephrine by lightly trained persons).
It's the same purpose, not the same usage. The administration is slightly different, the Adrenaclick injector doesn't have quite as fancy a safety cap and should be held in the thigh for longer.
http://www.goodrx.com/adrenaclick