S-Video Bulkhead has two 4-pin mini DIN jacks on each side.
The picture shows the bulkhead and the washers that ship with it. Notice the unique design - it has one fixed washer and the other can be threaded. The bulkhead can also fit Decora inserts or you can drill a hole on your wall plate to secure it.
It allows you to easily interconnect s-video cables while mounting this bulkhead on a wall plate or other plate.