These were made for a 28h DT RR465/RR1.1 rim and Powertap (Comp, SL, SLC) hub. These were a big hubs, so the hub cutout on the non drive side is 61mm. This means it will work with any smaller hub too. This also means it will fit over 6 bolt disc brake mounting bosses as well. They are at most 55mm across.
Although listed for a 28h rim, you can run it on other drilings by using electrical tape instead of the mounting screws. This is slightly more aero and quicker to do as well.
Comes with 2 sets of mounting hardware and valve hole covers.
$106.45 new.