Nikon SMZ645 Instructions Manual page 13

Insert the eyepieces into the eyepiece sleeves.
5
Be sure that it is inserted all the way until it touches the end of the sleeve.
Note) When inserting the 10X eyepiece, assure that it touches the end of
the sleeve, because the rubber cover of the 10X eyepiece will
obstruct the view of the sleeve end. When inserting, hold the rubber
cover not the diopter ring. If not, a failure could result.
The hexagonal wrenches can be stored in the rear of the pillar.
6
Refer to the figure on p.9.
II
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