Most adventurous high altitude trekking, crossing one or more passes of over 6,000 meter of altitude. General knowledge of mountaineering required. Nights will be very cold, daily 4-8 hours of walk at mountaineer's pace.
Treks and climbs of more than 15 days. Walking on very difficult grounds, basic mountaineering skills required. Nights at very low temperature. A strong resistance and a very good physical condition are required.
Treks of more than 15 days with daily stages of 4 to 8 hours. Differences in altitude of up to 1000m, below 4000m. One or more high altitude passes above 5000m. Most night's temperatures below freezing point. Sometimes-difficult camping sites. A good condition is a requirement.
Daily stages of 4 to 7 hours a day. The trails are usually well passable but some high altitude passes above 4000m can be steep. Possible snow on the high altitude passes can put your endurance to the test. A good condition is recommended.
Daily stages of 5 to 6 hours along good passable trails. Differences in altitude of up to 800m, below 4000m. Night temperature can drop below freezing point.