Factory Porsche alloy lug nuts, open ended and machined with a radius.  Popular on applications 
desiring the significant light weight advantage of the Porsche alloy lug nuts.  Since thread engagement 
is easily visible by any race tech official, these lug nuts are often approved for use in competition 
events, just like their steel counterparts, which have been known to damage the conical seating recess 
in aluminum wheels. 
$180 / set of 20