4/0, 18" Silk Black Braided Sutures with Reverse-cutting C-20 Needle, Box of 12 Suture Sets. Black sutures specifically made for wound closure applications. With extra sharp cutting edges. Smoothly penetrates into the tissue. Sold with silver C20 needle measuring 20 mm and with 1/2 circle curvature. 4-0 Silk Braided Sutures are non-absorbable sutures intended for closing wounds. These non-sterile sutures have a black dye, measure 18", and have a smooth surface that minimizes tissue drag.They are manufactured with non-capillary silk and have a braided design that enhances their tensile strength and effectively resists breakage during their insertion. They are delivered using the C20 needle with a reverse cutting needlepoint type.