From the Manufacturer:

A classic top-opening day pack that gives high performance, agility, and comfort.

Fully featured, it has proven to be a superb friend for many outdoor activities. Add Balance Pockets for two to three day trips.

Key Features:

• 2 back lengths with clip torso-adjust, 15 cm range
  
• U Flow, V Flow, and Flexi Flow
• Waterproof dri-liner
  
• 3 outside stretch pockets
• 1 lid pocket plus 2 liter hydration pocket
• Stretch front pockets 
• Auto-mould frame
• Auto-form hipbelt
  
• Closed cell foam sit mat
• Web-loc compression
• Ice axe, snowboard, snow shovel and trekking pole attachments
• Bodypack convertible with any model Balance Pockets

Compatible Options: 

• All Models of Balance Pockets
• X Flow chest straps
  
• Lasso-loc straps
  
• Ski straps
• Balance Gear Racks
• Tool quivers

Approx Volume: S: 30 L (1830 cu in)

Approx Weight: S: 1.3 kg (2.86 lbs)