This is the Blue Duratrax Single Arm Servo Arm. FEATURES: Aluminum construction, anodized blue in color Three plastic adapters allow horn to be used with Futaba, JR, KO Propo, Airtronics/Sanwa, Hitec, Tower Hobbies and Hobbico brand servos One large and one small diameter linkage holes INCLUDES: One Blue Duratrax Single Arm Servo Arm with three plastic adapters REQUIRES: Fastening to servo shaft SPECS: Thickness: 0.07" (1.9mm) Length: 1.1" (27.8mm) jxs 12/01/04 ir/jxs