This item is used on multiple models.
Notes regarding model 27:
According to the old 36B and 39B owners manuals, the 180 & 27 reels could use the same spools 29-100 and 29M-100. By which, we presume that the current aluminum reel 29L-100 can be used as a replacement for 29M-27.
As of 12/30/11, this has not be confirmed/tested.