Hello Jacques, the only Poseidon first stage we carry is the: http://www.scuba.com/scuba-gear-37/033071/Poseidon.-Jetstream-1st-Stage.html
. If you are looking for the other first stage. You can contact our repairs dept. at firstname.lastname@example.org and they might be able to order this first stage for you. If you have any other questions please feel free to give us a call at 1.800.347.2822.