Blackline Adjustable Spring Jaw Nipple Clamps. Spartacus Blackline nipple clamps are intended to make a striking visual statement with their black color elements All black link chain and adjustable rubber tipped spring jaw nipple clamps. Pressure is controlled by the screw on top of each nipple clamp. Spartacus A Passion for Quality Catalog page 12. New images added February 2, 2013.