This pack of Basil Bush Conical Gauzes are excellent for all types of bowls. They are already concave and extra strong. The screens are single-lined which enables them to be fitted to unique bowl shapes easily. A ring around the top offers extra support and stability. Easily remove from pipes to clean and reuse. Instead of wasting money buying screens every few months, why not spend a few dollars on these and reduce your waste?! The screens come in a pack of five for only about $2.50 at your local smoke shop or online at everyonedoesit.com. These little screens make a great, affordable gift. Why not buy these as a cheap stocking stuffer for that special smoker in your life?