Review on 🔩 Rivet Nut Assortment Kit - Zinc Plated Carbon Steel Flat Head Rivnut Threaded Insert Nuts, 140Pcs, 5/32"-32UNC, 8-32UNC, 10-24UNC, 1/4"-20UNC, 5/16"-18UNC, 3/8"-16UNC, 1/2"-13UNC by Jim Cox

I used them to fasten ducts in my construction trailer. No tool is required for installation. There are several videos online showing how to make your own using a screw and a few washers. Do yourself a favor and get a sheet metal step drill. Getting the hole size right really helps with installation, and a strep drill is easier to use than twist drills. I liked the variety set and the organizer. The organizer is thin, thin, the loop was missing. I wrote a letter to the company and they offered to either send a new organizer or refund $3. I took $3 because I knew a replacement organizer wouldn't be any better. But the organizer works, the labels are good, and I like having a full set of sizes for almost any screw-to-sheet metal fastener.