ZipSpring provides an easy end to an exhilarating ride. Our extra long 5.25’ long powder coated steel spring is made for use all of our Slackers Ziplines. The rubberized stoppers at each end protect the line, the trolley, and the rider with a smooth finish. Easy installation: Just feed the cable through the rubber stopper ends of the brake and you are ready to use your zipline braking system. If your zipline is already set up, you will need to remove the cable to install the Zip Spring.