From the Manufacturer:

With large front/back volume ratios, a body-centered load is easy to achieve with these new cutting edge designs. Pack them correctly and your balance and posture are unaltered by the load.

This combines with the low pack weight to give the most efficient load carrying system with ultralight gear. The pack and pockets have waterproof dri-liners. The Balance Pockets are removable.

• MT Balance Pockets included
• 1 back length with clip torso-adjust, 15 cm range
  
• U Flow, V Flow, Omni Flow and Flexi Flow
• X Flow Chest Straps with new Conus Clip buckle
• Waterproof dri-liners with roll top closures
• 5 external pockets
  
• Web-loc compression
• Foam, ice axe and trekking pole attachments

Compatible Options:

• Lasso-loc straps
• Ski straps
• Snowboard straps
• Tool quivers

Approx Volume: MT55: 37 + 18L (2257 + 1098 cu in)

Approx Weight: MT55: 1.49 kg (3.28 lbs)

Minimum Weight: (without dri-liners) MT55: 1.42 kg (3.13 lbs)

Key Fabrics: 420 HD nylon, 210D, 70D x 100D ripstop nylon