Have a sequin attachment that sews the sequins on, but it actually wouldn't be a good thing to stitch through sequins that are already there when talking about a fully covered garment. Typically sequins are used as accents compared to a 100% covered substrate unless that is all that's going to be done. Now if wanting to do multi-decoration on a garment, things have to be planned out a little big better. Locations, when/where to do what, design itself. That's not even getting in to how the sequins themselves are attached and what stitching may do to that as well if bounding through them. I wouldn't suggest stitching on a fully covered item with sequins.