A back up display for your Poseidon CCR will add redundancy and therefore safety to dive. ¬†This Bus Block cable has two female connectors and one male connector so you can run an extra display (either an M28 or a Paddle) with your SE7EN. ¬†There is no denying that there are advantages to using two different display systems.
(2 female Connections, 1 male)
This cable has two male connections and one female. ¬†Do not use this if you are looking to run two displays with your SE7EN.
(2 male Connections, 1 female)