This is the Futaba PS-01RS5.0 step down regulator.
Includes: Futaba PS-01RS5.0 Step Down Regulator with Connectors and Instruction Sheet
Requires: Installing between servo and HV compatible receiver or gyro
Main Application: 4.8V rudder servos
Input Voltage Range: 6.0 - 8.5V
Output Voltage: 5.0V
Rated Output Current: 1.0A (momentary maximum 5.0A)
Operating Temperature Range: -10 - +45C
Storage Temperature Range: -20 - +60C
Dimensions: 0.95 x 0.31 x 0.33 (24.2 x 7.8 x 8.3mm)
Weight: 0.18oz (5.2g)
Note: Do not connect between battery and receiver. The receiver may operate erroneously due to insufficient capacity and fail to control the model. Cannot be used with a Y-harness to supply power to multiple servos.