These clamshells are perfect for english paper piecing. They're cut from a wash away stabilizer often used for machine embroidery. Using this type of stabilizer will allow you to thread baste or glue baste your clamshells with Elmer's Washable Glue Sticks and then hand piece them together. Once the clamshells are basted there is no need to ever remove them! One pack includes 60 pre-cut clamshells.