I know - I've got a YouTube video on how to use the Q-Snap embroidery frames for side clamps.  I used them for years and had no intention of changing.  Until....a friend bought these for me!  They have a flat bottom, so you aren't as likely to bump into them and you can get away with a little less fabric on the sides.   They come in 12" and 18" lengths, this item is the 12".  The connectors are on sliders.  I have modified mine with small clamps so that they don't slide.  It's a control thing, do what works for the way you quilt!