Scubapro MK11 with S270 Regulator SetThe new S270 is also available with a MK11 first stage for divers seeking an airbalanced diaphragm design delivering effortless airflow unaffected by depth, tank pressure or breathing rate. The MK11s chrome plated marine grade brass body has sealed internal parts to prevent water and pollutants from fouling the inner mechanism while enhancing cold water performance. The new air balanced S270 provides smooth breathing performance in a bulletproof anti