Poolin06 Adult Size Sock Hoop Insert – Fits 5.5" x 5.5" (140x140mm) Hoops Perfect Fit for Poolin Embroidery Machines & Compatible 5.5" Hoops Upgrade your sock embroidery game with this custom 3D-printed adult-size sock hoop insert, designed to fit perfectly inside the Poolin06 5.5” x 5.5” (140mm x 140mm) hoop. This insert helps hold socks securely in place while stitching, preventing stretching and distortion for crisp, professional results every time.