The slider makes the surface slicker and makes the sandwich easier to move so it has nothing to do with your feed dogs as it covers them. I can attest that these devices make a huge difference. I have a sew slip II which is slightly larger than the queen slider and I used it all the time until I got my true glide overlay when I got my stitch regulator so I use that now. I also use machingers gloves and that also makes a huge difference