Precisions Dynamics Inc. has offloaded its medical writing instrument operation, the company announced Wednesday. Caledonia, Mich.-based Aspen Surgical paid an undisclosed sum for the division, which makes markers and pens used in hospitals and medical offices. Precision for the past several years has been refocusing attention away from its marker products in favor of bar code and radio frequency identification systems. Spokeswoman Paula Moggio said workers on the marker line have been transferred to other products. Aspen is a privately held company owned by Roundtable Healthcare Partners.