The "throat depth" of your sewing machine is the distance between the back of your sewing machine and the back of the sewing foot of the sewing machine. This defines the area within which the quilt will roll up on the frame roller. As the quilt is quilted, the roll of the quilt gets larger and the work area will be equivalently reduced. So, if your sewing machine has a small throat and you have a large quilt, you need to carefully plan the size of the designs that you will be able to create on your quilt. This limitation will be reduced significantly/ eliminated with the introduction and installation of the Max-Throat addition for home machine quilting frames.