This Allen-Bradley 1761-NET-ENI is an Ethernet interface that belongs to the Series C, with FRN 3.01. The brand, Allen-Bradley, is known for producing high-quality PLC processors and HMIs. This specific module is missing a screw for it's grounding port. (See pictures above) Other than that it works perfectly, and a substitute should be easy to come across especially if this is being purchased as a replacement. Simply swap one of the port screws from the old one into this. The simple task is represented in the price of the item.