| 摘要 |
The combination spectacles proposed comprise a frame and an attachment which can be mounted on the front of the frame, the front of the frame having, in the front surface at each end, a cavity designed to accommodate a projection on the attachment. Cavity and projection together form a snap-in-joint, the cavities being slightly longer in the direction of the longitudinal axis of the frame front piece than the projections which engage in them.
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