The flat base is used to sit the quilt on your lap as you use the hoop. You can also put your legs overtop of it on either side as you use it, or sit it ontop of a table as you quilt with it. I have a hoop like that, and they are great. I had a hard time learning to quilt with a hoop where I had to try to hold the hoop at the same time as I quilted, but once I got the hoop with the base (and it tips and swivels!), I learned quickly. Does that explanation help?
