If you have a Bernina sewing machine that was made after 1996 then you will require this adapter to be able to use the snap-on feet.  This item comes with two pieces: the shank adaptor (which will also allow you to use any low shank screw on feet, plus the snap on adaptor to use snap on feet. 

Compatible with Bernina Sewing Machine Models that are made after 1996:

Artista 730, 640, 635, 630, 200, 185, 180, 170, 165
Virtuosa 163, 160, 155, 153, 150
Activa 240, 230, 220, 210, 145, 140, 135, 131, 130, 125
Aurora 450, 440, 435, 430
Bernina 215, 330, 350, 380, 440QE, 530, 550, 560, 570, 580, 710, 720, 740, 750, 765, 770, 780, 790, 820, 830, 880

Please note this is a special order item can takes 2-4 weeks for shipping.