As referenced in a few 5-lug conversion threads, these are the 901/ 911 transaxle flanges that enable you to use 911 CV joints in your 5-lug conversion.
Thread by Eric:
http://www.914world.com/bbs2/index.php?sho...=91963&st=0
I've got 3 pairs of these flanges - looking for $80 shipped per pair
Thanks
Andrew M