Heat shrink tubing shrinks to 1/2 of it original size. Shrink tubing is the best way to shield open connections from short circuit scenarios. Made of high grade polyolefin and designed to protect to 600 volts, this tubing is deigned to cover everything from a butt splice to a Western Union Pigtail splice. Very easy to use, simply slide the tubing over your connection and add heat to shrink the tube to fit.