An upgrade in strength and strain relief over standard reducing splices. After crimping your splice, apply a heat gun or butane torch to shrink the plastic and grip wire securely under tension and vibration. The heat shrink also protects wire from the drips, dirt, and scuffs that lead to fraying, poor conductivity, and short circuits. Also known as step-down splices, reducing splices join a larger wire and a smaller wire end to end. Colored stripes differentiate the larger and smaller openings so you don't have to measure and mark them yourself.