If you are expecting wet conditions where down would be at a disadvantage, the Naturehike MG120 covers the same 5°C range with GRS-certified SUNDOUCE synthetic insulation.
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The field guide helps you choose based on skill level, temperature, needs, and weight. Support answers specific questions.
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The Aegismax Leto has a comfort temperature of 7°C and a lower limit temperature of 2°C, measured to the EN 13537 standard. These values apply under standard conditions: sleeper in thermal base layers, on an insulated sleeping mat. It is designed for hiking, trekking use (3 seasons).
The Aegismax Leto is filled with 700 fill power, RDS certified. The Aegismax Leto weighs 642 g, which places it in the ultralight category.
For multi-day trekking, the main criterion is weight: aim for under 1 kg, ideally between 600 g and 900 g. A high-loft down bag (700 cuin minimum) makes this possible while keeping enough insulation for mountain nights. The comfort temperature should match the area and season: 0°C to +3°C for the Alps and Pyrenees in summer.
Hiking generally means a day outing with no overnight stay, while trekking involves several days of walking with wild camping or nights in mountain huts. The distinction matters when choosing a sleeping bag: on a day hike, no bag is needed. When trekking, weight and packed size become decisive because the bag is carried every day.
In France, night-time mountain temperatures range between 0°C and +10°C in summer depending on altitude and area. A bag with a comfort rating between 0°C and +3°C covers almost all French routes (GR20, GR5, Tour du Mont Blanc) from June to September. Above 3,000 m or outside summer, allow an extra safety margin.