This is a 15T spline made of high-quality 7075 aircraft-grade aluminum. It features a REEFS machined shield design and is finished with a sleek black anodized coating. The spline is 3.11 inches long (79.1mm) and has 3 position holes at each end with double clamping for added security. It has 4mm threaded holes and comes with all the necessary clamping hardware and servo horn screw.