This is a NetBit switching power supply AC adapter plug.
It is a model DSC-51FL-52P adapter. It is black with a tag on the cord and a green light on the top side to indicate when it is on.
The adapter measures approximately 1.25" tall, 2.5" long, and 2.5" wide. The cord measures approximately 70" long.
It was made in China.
The item comes in very good pre-owned condition.