The term "HD" likely stands for "Heavy Duty" . A sewing machine marketed under an "HD 95" designation would typically be a robust, home-use machine designed to handle thicker fabrics and more demanding tasks than a standard model. A true heavy-duty sewing machine is characterized by a powerful motor (capable of up to 1,100 stitches per minute), a sturdy metal frame to prevent vibration, and the ability to sew through multiple layers of denim or light-weight leather.
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