Husqvarna Viking: 7, 19E, 21, 21E, 49, 51, 52, 90, 95, 105, 120,
 100, 105, 120, 150, 180, 185, 190, 610, 620, 630 old, 940, 945, 950,
 950S, 960, 980, 990, 990S, 1010, 1020, 1030, 1040, 1060,
 1070, 2000, 3000 Series, 3300, 3310, 3320, 3610, 4100,
 5430, 5530, 5540, 5570, 5610, 5710, 6000, 6010,
 6020, 6030, 6170, 6230, 6240, 6260, 6270, 6360, 6370, 6430, 6440,
 6460, 6470, 6570 & 6690 (does not fit 150E)
 Diameter 21mm, height 9mm, inside 6mm with slot