The patented, safe, flexible design of ET Flex allows you to adapt the strip to meet all of your interproximal finishing and contouring needs. Grip it at or above the crossbar and the strip is taut for contact areas. You can grip it below the crossbar and the strip curves, and it allows you to perfectly adapt to any contour. For more information, call (800) 842-4522 or visit brasselerusa.com.