The spline socket design offers higher strength in a more compact profile, making it common on military and commercial aircraft. Urrea spline sockets are made from high quality steel. Polished chrome plated finished. Spline size: 26. Type: II. Inches: 13/16”. MM: 20mm. Length: 5/32″. Nut end outside diameter: 1/2″. Drive end outside diameter: 1-5/32”. Nut depth: 5/8″.