This is the Heavy Duty EZ Connector set by Dubro. EZ Connectors link a pushrod to a servo arm allowing it to pivot for less bind in control surfaces. FEATURES: Steel construction INCLUDES: Two steel E/Z connectors (drilled for 4-40 pushrod wire) Two steel retaining washers Two 4-40 x 3/16" cap head screws for securing pushrod wire REQUIRES: 4-40 linkage pushrod. 3/32" allen wrench to tighten screws 3/32" hole in servo horn. Note:Rudder in picture not included!