This is the GY240 Gyro with SMM Technology from Futaba.
This is a High Performance, Compact and Lightweight
(AVCS) Angular Vector Control System gyro developed for model helicopters.
Because the sensor and control circuit are integrated, it is simple to install.
One Year Warranty

FEATURES: AVCS System: (Heading Hold) Since the rudder trim changes
(caused by wind and other meteorological changes); the front,
rear, and other heli attitudes change and are automatically
cancelled; tail (rudder) operation is easy, making it perfect for
3D Flight.
SMM Gyro Sensor: Use of this newly developed technology virtually
eliminates rudder trim changes during flight (see COMMENTS).
Integrated, compact and lightweight design made possible by high
density mounting technology.
Conductive Resin Case: This case improves EMC (Electrostatic and
electromagnetic interference) resistance.

INCLUDES: One GY240 gyro
One mini plastic adjustment screwdriver
Three mounting pads
One instruction sheet

SPECS:    GY240 Gyro-
Length: 1-1/16" (27mm)
Width:  1-1/16" (27mm)
Height:   3/4"  (20mm)
Weight: 25g
Voltage- use only with a 4.8V battery. (if you use it with a
higher voltage battery it needs to be regulated to 6.0V)

COMMENTS: Can be used in helicopters and airplanes (Due to 0-100% Gain Adjust).
The new SMM (Silicone Micro Machine) technology is the integration
of mechanical elements, sensors, actuators and electronics all
brought together on a common substrate chip. This hobby industry
first, results in a gyro sensor with an unprecedented level of
functionality, reliability, and sophistication.
This gyro performs best when used with non-digital servos.