Coxreels SD-50 Spring Rewind Static Discharge Cable Reel: 50' cable is part of our SD Series COXREELS® selection. COXREELS® SD Series “Static Discharge” cable reels are built heavy duty and designed for long lasting performance. They are specifically design to be used in combustible environments where the static buildup could ignite a spark and subsequent explosion. Static discharge or grounding reels are commonly paired with fuel hose reels found on page 33.