No need to recalibrate the irradiation point — The LED lamp holder and the battery compartment of the control switch are designed separately, which is beneficial to not change the irradiation point of the light source during operation, and does not need to recalibrate the irradiation point when repeated operations. The eye mask can be moved 5 cm left and right on the stand, and the width of the face and the distance between the left and right eyeballs can be adjusted.magnifying glass repair kit — 1 x Glasses Stand, 2 x 10 Times Magnifying Glass, 2 x 15 Times Magnifying Glass, 2 x 20 Times Magnifying Glass, 2 x 25 Times Magnifying Glass, 1 x Headband, 1 x User Manual in Chinese and English.Replacement battery — Press and hold the switch, the battery cover rotates 30 counterclockwise to the left, the battery cover will pop out by itself. Then take out three LR1130 batteries and replace them with new LR1130 batteries with negative s.Switch operation — Rotate the battery cover in the direction of CW from the small dot to the light-colored symbol by about 40. At this time, turn on the LED light source, CCW and turn off the light source. You can select the appropriate magnification lens barrel according to the size of the observation object.prompt — If you need to work with this magnifier for a long time, you can use the two lens barrels alternately to eliminate visual fatigue and improve work efficiency.