The Tconnector is used to install and connect to the main line to add a branch line connection. The standard Tconnector can also be attached with a cover to temporarily protect the connector for future connection of diagnostic instruments. The Tconnector can be matched with all other devices on the network that use the same type of connector.instrument network to interconnect marine electronic devices. It is multimaster and self configuring, and there is no central network controller. Equipment designed to this standard will have the ability to share data, including commands and status with other compatible equipment over a single channel. It is based on CAN (Controller Area Network)One NMEA 2000 TConnector for every device and accessories that are connected to the networkOne NMEA 2000 TConnector for the NMEA 2000 Power CableOne NMEA 2000 Drop (Backbone) cable (no longer than 20 feet) that will connect each device or accessory to its own TconnectorNote:Installation guide not included,Please check as much as possible to make sure the item is what you need.Tips: The product may be updated constantly ,Due To Different Batches, The Actual Product May Have Slight Differences Or Color Differences, Which Does Not Affect UseColor: blackMaterial: plasticPackage Contents:4 X NMEA2000 ConnectorOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/ 13cm.