Square Feet are designed to aid in achieving straight seams while piecing on your quilting frame. These feet can be used as a guide for consistent seam allowances of 1/4 inch and 1/2 inch. The 1/4-inch Square Foot is great for cotton fabrics, the 1/2-inch Square Foot is best for cuddle type fabric and high loft batting. Compatible with all HQ machines with Interchangeable Foot Mount. NOTE: All optional Handi Quilter feet for HQ longarms require your Handi Quilter machine have the Interchangeable Foot Mount. HQ machines manufactured before November 2014 may need the Handi Feet Conversion Kit installed to make optional feet compatible with your machine.