"SewTites are a way to pin when you can't -- magnetic ""pins"" for sewing super thick materials, like leather or cork, or pieces that aren't near an edge, like pockets on bags. Using SewTites means no more pin holes. They easily keep thick materials together and won't break like clips. SewTites make working your English paper piecing projects easier than ever -- no more hand cramping or fatigue holding pieces together and no more working around (or moving around) clips and pins. To use, simply slide the magnet apart, align with the pieces you need to sew together, snap on the SewTites, and sew. SewTites are safe to use with computerized sewing machines, however, do not store SewTites on your machine. Use this 10 pack of SewTites Dots when working on small EPP projects, wool applique, and more! The magnets in the Dots are extremely powerful and will hold very thick projects together; since there is only one magnet on the Dot, they work well when you want to move around the magnet somewhat while working. If you need something slightly larger that will not move around, check out the SewTites Mini. SewTites Dots Dimensions: .67 in. (17mm) diameter."