Promotional diagnostic flashlight pen is use of acrylic bubble, portable holding clip, can be arbitrarily clip in the pocket, neckline and other places, easy to use, easy to place. Tail alloy switch, can open single-light cycle mode. The cylinder body is engraved with a scale of 50mm in length, which can be used for daily simple measurement, fast and convenient. The tube body with pupil control data for routine examination is recommended for use by neurosurgeons. Physical reverse connection technology is adopted to prevent oxidation. Poor contact and other phenomena to improve efficiency.