This is the Futaba S3004 Light Weight, Ball Bearing Servo.
This basic servo is used in cars, boats, or where standard servos are used.
Note: This servo is not designed for use with glow-powered helicopters.
This is a replacement for the following servos.(S15)

This servo can produce high-current draw from your batteries.
If using NiMH or LiPo batteries, make sure they are capable of delivering sufficient amps.
FEATURES: Single ball bearing on output shaft
Precise tight fit throughout the geartrain
Being standard size and lightweight, it fits many applications.
Three pole motor
Nylon gears
One year warranty
INCLUDES: One S3004 standard servo with preinstalled round servo horn(FSH6W)
Four brass eyelets
Four Black one-piece rectangular rubber grommets (FUTM2348)
Four servo mounting screws
Three servo horns (1 lg. round, 1 lg."X" and 1 sm. "x")
Connector: "J" type with approx. 5" wire
SPECS: Speed: .23 sec/60¦ @ 4.8V
.19 sec/60¦ @ 6.0V
Torque: 44 oz-in (3.2 kg-cm) at 4.8V
57 oz-in (4.1 kg-cm) at 6.0V
Length: 1.6" (41mm)
Width: .8" (20mm)
Height: 1.4" (36mm)
Weight: 1.3 ounce (37.2 grams)