SSP-4 Spine, 3"x 1" spine on one side and a 2" x 1" spine on the other. Use the S Spine in your quilt borders, sashing, and blocks to create beautiful custom quilting. The Spine is made of 3/8" clear acrylic and has a beveled edge and special markings to assist you with precision quilting. See video at www.terylloy.com/videos/ for examples on use. *Note: Some brands of long arm hopping feet do not have enough clearance on the back side of the foot to accommodate a 3/8¿ template. Use may be limited to the other sides of the hopping foot.