On the 500 and 500S reels:
This Part is used with the FINE-TOOTHED Bridge/Star/Sleeve System.
Click Here for More Info On Design Change
Standard on the other reels that use it
About the two different runs of 10-505 drag stars
This was discovered 4/2012
It is not related to the fine-toothed thread info above. It is a separate issue.
Penn did a more recent manufacturing run of these 10-505 stars.
They changed the machining of the fine thread just slightly enough to cause an issue with the newly made stainless sleeves, as described in the photo notes below.
SIMPLIFIED
If you only intend to use the 98-505 brass gear sleeve, order 10-505-B.
If you might, or are, changing to the
98-505AT stainless steel sleeve, order 10-505BS that fits both.
The 98-505PRO stainless steel sleeve fits both versions of the star.