Aluminum is the material of choice for higher performance. For this purpose, Sapim has chosen the highest aluminum grade possible (7075 T6) for this sort of usage. It combines light weight, strength and corrosion resistance. The anodized surface treatment provides various color possibilities.
Sapim ensures that aluminum nipples receive a special coating that reduce the friction. The Sapim coating is a unique process that applies on the thread and the nipple surface. Friction between both spoke and nipple and rim and nipple are significantly reduced.
Coating also seals the surface reducing corrosion:
Silent, effective truing with no more squeaks
Virtually torsion free spokes
High tension wheels without problems
No over tight nipples on spoke threads
No more oily and dirty wheels
Just efficient dry working and clean hands
No unnecessary cleaning
Wheels are easier to true
Buying Guide - Handbook
What to look for and things to consider before you buy