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Sports Lenses 197

Fig. 14.6: Step no 1

2. Prepare the measuring aid : The easier way to take the measurement is to
prepare the measuring aid as shown in the Figure 14.7, setting knob (1)
back, measuring arms (2) and (3) closed.

Fig. 14.7: Step no 2

3. Place the measurement aid on the frame: Now place the measuring aid onto
the frame. When you place the aid, the measuring arms open. Make sure
that the guide bar (4) is apposed to the upper edge of the frame and the
mid marking of the guide bar accords with the frame mid point (Fig. 14.8).