This is the Futaba S3151 Digital Servo.Great for a multitude of R/C models. FEATURES: Digital technology offers performance benefit.Dual Ball BearingsPlastic gears INCLUDES: One S3151 Digital servo with preinstalled servo hornFour Rectangular GrommetsFour BushingsFour Mounting ScrewsOne Large Round HornOne Six Arm HornOne Four Arm Horn SPECS: Speed: 0.21 sec/60 levels at 4.8VTorque: 43.1 oz/in @ 4.8VDimensions: 1.59x0.79x1.42 in (40.6x20x36mm)fat: 1.48oz (42g)