3Sixteen Square Sunglasses

A square frame does the opposite of what a round one does. Where the round softens, the square holds a line: it draws a horizontal across the face at the brow and squares off a face that is already soft or long, and it reads as more deliberate from across a table. It is the more graphic of the two shapes and the less forgiving, which is why the execution matters more.

Eight-millimetre acetate is the reason this one holds its geometry. A square front cut from thin material bends at the corners and loses its shape within a year, and the corner is exactly where the shape lives. At this thickness the front stays square, the bevelled edges catch light along their length, and the frame has the weight in the hand that separates a cut-acetate front from an injection-moulded one. The metallic logos are small and set discreetly at the temples, which is a decision worth noticing on an object that spends every day on someone's face.

The acetate is bio-circular, made from renewable and recovered feedstock rather than conventional petrochemical sources. It behaves like any good acetate; the difference is upstream, at the material.

Sizing and dimensions

Frame width 145mm, lens width 50.5mm, bridge width 22.5mm. The 145mm front is medium-to-wide and suits most adult faces without crowding a narrow one. At 50.5mm the lens is three millimetres wider than the round frame's, which is what gives the square its presence: it covers more of the face and reads as the bolder of the two. The narrower 22.5mm bridge sits closer to the nose than the round's, so if the round frame felt low on you, this one is likely to sit better. Acetate can be heat-adjusted at the temples and the nose by any optician, so a frame that is slightly off out of the box is usually a five-minute adjustment rather than a wrong purchase.

How they are worn

Genuinely unisex, and worn by both. The square is the frame to choose if you want the eyewear to be the most deliberate thing you are wearing; the round is the one to choose if you do not. Against the rest of the 3Sixteen range, which is workwear and military patterns, either reads as the single considered piece of design in a practical wardrobe.

The hinge is the honest answer. A five-barrel German steel hinge is the difference between a frame you own for a decade and one that develops a wobble in a year, and it is invisible at the point of sale, which is why most eyewear does not have one. We also wanted frames a customer could take straight to an optician, because we are not interested in selling sunglasses to people who need to see. And it let us carry something from this house that is not menswear, which matters more than it sounds.

3Sixteen made the eyewear outside its usual production entirely, in Italy, which is where acetate frames of this construction are actually made.

Eight-millimetre bio-circular acetate. Five-barrel German steel hinges. Discreet metallic logos. Lenses with full UV protection, and the frame will accept optical lenses. Made in Italy.

Acetate does not like heat, so keep them out of a hot car and off a dashboard, which is what warps a front. Clean the lenses wet with a soft cloth rather than dry, because a dry cloth grinds grit across the coating. Store them in the case. Our general care guidance covers the rest.

The same construction in a round front is the Round Sunglasses. We wrote the frames up in the Library when they arrived, and that piece is 3Sixteen eyewear.