Both firing and non-firing prop models of the E-11 were based on the Mk 4 Sterling submachine gun, with approximately 20 models built for the first Star Wars movie A New Hope. External modifications to the Sterlings to transform them into blaster rifles varied based on the parts available but most were similar in design. This included an American Mk38 azimuth tank scope and a Hengstler industrial counter box affixed to the top and left side of the receiver respectively.