A traditional clip-on lenses require four hooks to securely fasten the clip to the front frame; Lineus features a notch beneath the temple, allowing a sun clip to seamlessly attach to the frame’s exposed titanium core using just two side hooks.Lineus’s temples feature two pieces of acetate, connected by a titanium core; the titanium allows for flexibility and reduces tension at a critical juncture, ensuring comfort while repeating the frame’s signature cutout detail