flybold Slackline Kit
Patience, young grasshopper. Patience, balance, coordination, and peace with falling on your face a few times. These are the things you'll need to master the flybold Slackline.
According to flybold, this "COMPLETE Slackline Kit is as complete as a slackline kit can get," which sounds both ambiguously reassuring and like a line someone would throw down in a rap battle. Probably me because it's not really very good. The setup comes with a 2" x 49.2' webbing strap with covered loop to serve as the main slackline, plus a training line that's the same length and material, but 1" thick. You'll also get ratchets for both lines, attached to 8.2' long x 2" and 1" wide flexbands respectively. An arm trainer 1" x 4.6" webbing strap completes the overhead training wheels from the kit.
flybold includes a ratchet protector for the main slackline and 2 tree protects, plus a carry bag so you can transport and set up your slackline in the park when you get good. As long as you find the ideal pair of trees first, before any of the barefoot shirtless dudes with hemp necklaces (who are surely sons of the dudes who played hacky sack in the park when I was a kid) get there.