Sinuous Springs No-Sag, S-coils, zigzag wire, zig zag springs, serpentine springs ? are all the same thing, but with different names. These springs are very easy to use and are great for ottomans, chairs and sofas (seats and backs), etc. They install quickly and easily and don't require a time-consuming hand-tying effort like coil springs. Simply run rows of springs every few inches apart, either side-to-side or front-to-back. (clips sold separately) For chair and sofa backs - Soft (11 gauge 120ft reel) For seats, sofa seating and ottomans - Firm (8 gauge 120ft reel) Medium Firm (9 gauge 120ft reel) Spring clips sold separately (100pc bags) Additional Details ------------------------------ Product description: Sinuous Springs No-Sag, S-coils, zigzag wire, zig zag springs, serpentine springs ? are all the same thing, but with different names. These springs are very easy to use and are great for ottomans, chairs and sofas (seats and backs), etc. They install quickly and easily and don't require a time-consuming hand-tying effort like coil springs. Simply run rows of springs every few inches apart, either side-to-side or front-to-back. (clips sold separately) For chair and sofa backs - Soft (11 gauge 120ft reel) For seats, sofa seating and ottomans - Firm (8 gauge 120ft reel) Medium Firm (9 gauge 120ft reel) Spring clips sold separately (100pc bags)