This is the Futaba S3003 Standard Servo.
This basic servo is used in cars, boats, 

or where standard servos are used.
This is the replacement for the following servos,

 S138,S148,S22,S38 and S12.

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.

INCLUDES: One S3003 standard servo with preinstalled round servo horn FUTM0031 Four brass eyelets Four Black rectangular rubber grommets (FUTM2348) Four servo mount screws One servo wheel 1-3/8" (35mm) in diameter One X shape servo arm 1.5" (38mm) across One star shaped arm 1-1/4" (32mm) across Nylon gears One year warranty

SPECS: Speed: .23 sec/60° @ 4.8V or .16 sec/60° @ 6V Torque: 44 oz-in @ 4.8V or 56.8 oz-in @ 6V (3.2 kg-cm @ 4.8V or 4.1 kg-cm @ 6V) Size: 1.6"L x .8"W x 1.4"H (41x20x36mm) w/o output shaft Weight: 1.3oz (37.2g) Connector: "J" type with approx. 5" lead

Volts	Torque	Speed
4.8V	44.4 oz-in.	0.23 sec/60°
6.0V	56.9 oz-in.	0.19 sec/60°
Dimensions		Weight
1.6 x 0.8 x 1.4 in.		1.3 oz.