It only takes two trees and the spirit of adventure to start zipline in the back yard all while riding a just a few feet off the ground. Install with confidence knowing the #1 U.S. Zipline company has time tested, high grade components for strength, reliability and longevity and full warranty policy. Follow the directions and your zipline will be set up in 30 minutes. Series Kit Zip Spring 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.