Curious model 15 on ebay.  From the keyboard, it appears to have a financial typeset.  I notice a two color ribbon and a mystery box to the right of the carriage.  Also some unidentified control / button on the lower right hand side of the keyboard.  

Not mine, or associated with anyone I know, yadda yadda.  Just curious if anyone knows anything about it.  Was there a mod for the 15 to use a two color ribbon?  

Cheers,

Keith