Yellow colored feather shuttlecock helps provide a better visibility on light colored wall, e.g. the common gymnasium here in the US.

Precision Super "A" feather shuttlecocks are produced using the highest quality components and the most advanced manufacturing techniques, in order to meet rigorous performance standards. Black Knight has made them to be the finest feather shuttlecocks, excelling in flight, reaction, consistency and durability.

Recommendation:
To prolong the durability of the shuttlecocks, we highly recommend that all shuttlecocks be humidified 24-48 hours before usage. This will help increase the life/durability of the shuttlecock by up to 70%. Please check http://www.shuttlecock.com/Resources/Shuttlecock/hydrate.php for tips on hydrating shuttlecocks.