This is an optional Hot Racing Arrma 4x4 Fixed Link Steering Servo Saver, an aluminum servo saver with Fix Link steering for Arrma 1/10 Steering applications.
 
Features:
CNC 6061-T6 aluminum construction
Black anodized
Multiple inserts to accommodate many different servo splines
Specifications:
Length: 34mm
Diameter: 23mm
23 tooth (KO, Sanwa, JR, Airtronics, Spektrum)
24 tooth (Hitec)
25 tooth (Futaba, Traxxas, SAVOX, Tactic, new Hitec)
 
Includes:
(1) Aluminum Fix steering link.
(1) Servo saver
(1) Spline adapters for 23 tooth (KO, Sanwa, JR)
(1) Spline adapters for 24 tooth (Hitec)
(1) Spline adapters for 25 tooth (Futaba)