I found mine and it's for the smaller case. I compared it to the 66, and it's the same width but about 3/8" to 1/2" shorter. DH thinks I may have a base this fits in out in the shed, so I've got to go check on that. Both of the two 3/4 size bentwood case I have machines in have the older style with the two holes for the electrical, and they aren't easily removable as they cover the control and use a knee lever.