I am building a dust collection system for my wood shop in my basement. I needed a way to close off the two ends of the main collection hose which is 2.5” in diameter. I came across these tapered rubber stoppers by searching the internet. I ordered two. They arrived in three days. I put the thinner end into each “Y” at each end of the main hose and gently tapped them in place with a rubber mallet for a snug fit. I didn’t even have to clamp them into place. They work great. Maybe not the use for which they are intended but the stoppers fulfill the need. Thank you!