These specialty coated, large eye needles allow the thread to pass through more freely at high speeds. The pontoon scarf (the indentation above the eye) reduces the chance of skipped stitches and thread breaks as the fabric is flexed up and down by the rapidly moving needle. Klasse Titanium Embroidery Needles work best with rayon, polyester, cotton and acrylic embroidery thread. These needles have a unique curved design at the clearance-above-the-eye stress point that helps distribute equal pressure, making the Klasse Titanium Embroidery Needles much stronger than other flat conventional needles.