And same for the 2nd stages: Shark, Nemo and Chinook look the same inside. Chinook is the name for the nitrox version (green deflector), but this reg seems young enough to have all epdm o-rings inside, so the difference may be just color and cleaning procedures. As noted above there is an original and an upgraded version of the Shark, which is the only major difference. There is a main tube with short flats and another with longer flats to attach the hose. And the mouthpiece adapter can be exchanged for the P-port, and it seems these are delivered with hoses that have an integrated OPV and do not vent into the reg but into the water (I wonder if the integrated OPV in the 2nd stage differs in these versions). Finally, there are black, grey, yellow and green bubble deflectors. And it seems that sums up the variation in 2nd stage versions.
