Down Suits from both North face and Mountain hardware, hood with oxygen masks covering your face, and plenty of socks are essentials.
The Himalayan ranger is much colder than you think. So you will need multi-layer clothing for climbing Mount Everest as the temperature changes dramatically. Carry a light-weight down jacket all the time, wear water-resistant gloves, and good pairs of down mittens higher up. Wear a heavy down suit from camp 2 to the summit. Down Suits from both North face and Mountain hardware, hood with oxygen masks covering your face, and plenty of socks are essentials.