From the manufacturer's official website:

The profile of the teeth is designed with Ultra-Drive™ geometry which facilitates the passage of the chain on the sprockets and makes shifting precise, fast and silent. Available from this year, the 11-25 combination is ideal if combined with CT™-type cranksets.

Ultra·Drive™ - single sprockets - nickel-chromed finish - supplied without lockring (except 11-25).

Nominal weight: 250 g.

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