This is the Futaba S3305 High Torque, Metal Gear Servo.
per Futaba this servo is approved for use with NiCd batteries ONLY!

It can produce high-current draw from your batteries if using NiMH or LiPo batteries, make sure they are capable of delivering sufficient amps.


FEATURES:
Wide usage in cars and boats that require standard size, high torque servos
Two ball bearings
3-pole motor
Standard Futaba J style connector
Metal gears
One year warranty

INCLUDES:
One Futaba S3305 High Torque Metal Gear Servo with 1.5" (39mm) diameter horn, 1.2" (32mm) 6 point horn, 4 eyelets, 4 rubber grommets, and 4 mounting screws

SPECS:
Dimensions: 1.6 x 0.8 x 1.5" (40 x 20 x 38mm)
Weight: 1.7oz (47g)
Speed: 0.25 sec/60¢X @ 4.8V
0.20 sec/60¢X @ 6V
Torque: 124 oz-in (8.9 kg-cm) at 6V
99 oz-in (7.1 kg-cm) at 4.8V

COMMENTS:
Gear set FUTM3384 or DTXM3505
Case set FUTM2948
Futaba recommends these for cars and boats.