Image: aernhardt @ ebay
Found this from the bay... very interesting...
The Roval hidden nipples utilize a three-piece design to improve nipple alignment,
which reduces spoke fatigue and improves wheel durability.
Our exclusive larger diameter nipple design distributes the loads across
a wider surface area for further improvements to strength and reliability
DT SPOKES Our custom DT Swiss stainless steel spokes never fail to
surpass the competition in both quality and endurance.
They're aerodynamically shaped with a thin profile for superior performance,
and the straight-pull design not only creates a uniquely shaped hub,
but improves reliability.
A ROVAL HIDDEN NIPPLE TECHNOLOGY