These are the Dubro Super Strength Long Servo Arms for Airtronics and Hitec servos.
Includes: 2 each of short, medium and long servo arms that extend in one direction from the servo center. Also has two long arms the extend in two opposing directions from the servo center.
Specifications:Short:Mounting holes at: 12, 15 and 18mm.Total length-22mm.
Medium:Mounting holes at: 15, 19, 22 and 25mm.Total length-28mm.
Long:Mounting holes at: 23, 25, 28 and 32mm.Total length-36mm.
Dual:Mounting holes at: 15, 19, 23 and 26mm.Total length-58mm.
* All measurements are from the center of the arm. * The dual is only from one side to center.