Trellis Coil for AG?

Just wondering if this would be usefull for growing or not.. I am not even 100% what it does or howto use it lol.

"Additional 4-pack of trellis coils to keep your plants stable and strong, with our new easy-to-use trellis system. It supports large plants, such as tomatoes and peppers, using a simple, spring-loaded pulley system. Includes 4-coils for use with your existing Deluxe Trellis System."

I looked at that for a while and I think it's one of those retractable ID-card holders.

Retractable Badge Reels, Holders, Clips: ID Cards, Name Badges and Key Reel Supplies