help with ebay listing

[Lunatic]

I'm parting out my '81 XS11 Special and wanted to list the "ignition unit" box but I dont' see a part number on it at all. Which box would this be? I want my ebay listing to be as informative as possible and that would help. thanks

[bikerphil]

The 81 Special uses a 4R0 box, it will work on only the 81 Special, 81 Midnight Special, and the 81 Standard (Venturer).

[Lunatic]

Excellent, thanks.
Here I was thinking it was a 6 letter/number designation.

[DGXSER]

The 81 4RO box typically has a yellow sticker on it. Yours may not have it anymore. The previous ones had 2H7 stamped in the black plastic.