hi, i was just wondering if anybody out there knows of any surface air valves that could be used with this mask, i've seen the OCEANREEF SURFACE AIR VALVE at http://www.scuba.com/shop/diving.asp_cat_124_scuba_1_gear_027341_pn_OCEANREEF-SURFACE-AIR-VALVE, but cant find any for the POSEIDON, any help would be great, thanks everybody