TL;DR This is an important tool for holes that are too large for sealant to handle alone. It's easier than installing an automotive plug and not a bad price for the convenience this product provides.I'm a commuter in Honolulu, and we have terrible roads and not much better bike paths. Broken glass is relatively common, and some of the thorns will go straight through the sole of your shoe. It's not ideal for cycling, and I'd be changing a tube every week or two despite having the best tires I could afford.In a fit of inspiration, I decided to go tubeless a while back. I bought this tool when I ordered the tires. The intelligent man running the bike shop in Honolulu put some sealant in there, which was good enough for six weeks of trouble-free riding. Eventually, I did hit something larger, and sealant bled out of my tire as though I had spilled milk on the road. Crestfallen, I kept spinning my tire and trying to get the sealant to do its trick. Like an idiot, I wasn't using the plug. Mostly because I was afraid that I'd mess it up in the field.After stopping and using an air pump, I heard the sealant give way with a horrifying hisssss. It took me literally seconds to: Grab the tool from the bottle cage, uncap one-end and jam the plug in there. It stopped immediately, needing only a little trim to finish up. It's been about a week, and the plug seems fine. Price-wise, I feel like I've gotten a good deal. The tool costs a bit, but it's well made and most importantly it is sealed and ready-to-use when needed. I didn't need to play with any solvents, or try to manipulating a gooey little elastomer with dirty/greasy hands.