Du-Bro Heavy Duty Clevis Horn System \(8-32\) Part No: 3355. A complete mounting system for large aircraft that can be configured as a pull-pull or as two single control horns. Self-adjusting design will mount at 90 to center line of the control surface. This system includes premium socket head bolts which provide a non-slip head while installing horns. The clevis horns include 4-40 heavy duty swivel ball links for "no-slop" precision control.