There are two types of 1/4" presser foot type attachments. I found this out the hard way. There's the regular kind and the quilter's 1/4" presser foot. I was in the middle of a project and had to purchase a replacement. Wouldn't you know the regular quilter's assistant was out and as luck would have it, I purchased the wrong one. My block was smaller on the side I pieced after the replacement!