This is a 1550nm Variable Optical Attenuator. Its attenuation range is 0~30dB, which is adjustable. The adjustment step of the attenuation value is 0.1dB. Single-mode optical fiber is used here. It supports both button adjustment and software control. Connect to PC software via RS232 communication interface.
The control software interface.
Instructions for use:
Turn on the power switch at the back. Use the buttons to adjust the attenuation value. The left and right buttons are used to select the digit to be adjusted. The up and down buttons adjust the corresponding value.
The test report of this optical attenuator. 
