The HoopKeyDoo is a must-have for every sewist who owns a Bernina embroidery machine. This handy tool effortlessly tightens and loosens your embroidery hoop screw; saving you time and preventing finger strain. Get a better grip on thick materials and stabilizers using the HoopKeyDoo. The HoopKeyDoo is compatible with all Bernina embroidery hoops; excluding the Jumbo Hoop. The Hoop Key Doo is made in the USA.