This product is a tool designed for use with 10BASE-T and 100BASE-TX networks. The monitoring ports are J3 and J4, which are receive-only. To use, connect the Ethernet cable to be tested to J1 and J2 of the LAN Tap, allowing J1 and J2 to receive data. Then connect an Ethernet cable to J3 or J4 of the LAN Tap, as each port detects one direction of data communication. Use network analysis software such as TCPDUMP or Wireshark to capture and analyze network traffic on a connected workstation. This device is intended for Ethernet network monitoring and data analysis. Color: Black & Silver Material: PCB Package Contents: 1 x LAN Tap Note: Light reflection and different display settings may cause slight variations in the color shown in the image compared to the actual item. Measurement may vary by +/- 1-3 cm.