Christy,
the numbering is confusing. The Boye numbers go from 1- 27, and include 2.5 and 20.5 as those are needle sized added at a later date.
Those numbers include both shuttles and needles,
#1 is the shuttle and long bobbins that fit Household Mfg machines
#2 is the needle that fits the Household machine
One very interesting item, the picture on the case does not always match the shuttle. I'll need to do more research, but I think that over time Boye may have changed the shuttle design slightly, but left the picture as it was OR the picture is what the original MFG shuttle looks like, and not the BOYE aftermarket one.
There is also a BOYE chart that shows foot type as a guide to help identify machines. This is what got me very interested in the Boye supplies, since I'm very interested in the attachments.
Some interesting reading
http://needlebar.org/main/boye/index.html
and the Twin Boye
http://needlebar.org/cm/thumbnails.p...ds=on&type=AND