From the manufacturer's official website:

The wide pivot link design boosts strength and rigidity. Flex is suppressed, creating sharp, precise shifts that are faster and smoother, even from low to high gears off of the saddle.

Features:

• Wide link design : 20% increased rigidity.
• Pivot locations for less cage deflection : Pivot location at cage was moved to the point of maximum force to reduce cage deflection.
• Narrower chain cage : Narrower chain cage to accommodate 10-speed chain.
• Hyperdrive compatible
• Light action spring
• DUAL SIS front index shifting
• Specially-designed for 10-speed
• Capacity : FD-5600 16T, FD-5603 20T (specially-designed for FC-5603)

Specifications:

• Rear Speeds 10
• Front SIS Yes
• Chain Ring Double
• Link Type Conventional
• Mount Type FD-5600-B FD-5600-F Clamp Band Brazed-On
• Applicable Chainline 45mm
• Clamp Band Diameter FD-5600-B *(28.6)/31.8/ 34.9mm
  *W/Multi Clamp Band
• Top Gear Teeth 50-56T
• Capacity 16T
• Chainstay Angle 61-66 degrees
• Compatible Adapter FD-5600-F SM-AD11(31.8mm) SM-AD15(34.9mm)
• Front Clamp Band (FD-5600-B) Material/Finish Aluminum/ Clear Coated
• Rear Clamp Band Material/Finish Aluminum/ Clear Coated
• Outer Link Material/Finish Aluminum/ Clear Coated
• Inner Link Material/Finish Aluminum/ Clear Coated
• Chain Guide Material/Finish Steel/ Chrome Plated

For more information, please visit this product's webpage.