It's a 99-13; Electric portable with wooden cover or carrying case, knee control. I got mine from
http://www.shopgoodwill.com the machine cost me 22.00 and the shipping was 33.74 so it totalled out at 55.74. Mine is in really good condition. I do plan to rewire it because of the age of the wiring. I've seen the 99's there quite often.