Hermes Royal Belt Buckle & Reversible Leather Strap 38 mm Epsom Calfskin Palladium Buckle Silver Bleu De Prusse Noir

Prussian blue is a colour that only shows its depth in person: dark enough to pass as black across a room, distinctly blue in daylight, and completely at home with grey and denim. Here it lines one face of a 38 mm reversible strap, with noir on the reverse and a palladium buckle between them.

The leather is Epsom calfskin, heat-embossed for that fine, even grain. It is firm, matte and resistant to scratches and moisture, which is exactly what I want from a belt that spends time on planes, in cars and against the backs of office chairs. Palladium keeps the hardware cool and understated rather than golden and loud.

In rotation, the blue face goes with charcoal flannel, chambray and stone chinos, and the black face goes with almost everything else. Flipping means rotating the buckle; the strap edge always shows a sliver of the colour you are not wearing, and the Royal plate stays a broad, plain shape rather than a logo. The blue reads formal in winter and relaxed in summer, which is a useful trick for one belt to have.

Points to weigh: Epsom needs a few wears to soften at the fold, and at 38 mm the strap can be snug through narrow trouser loops. Nothing that has bothered me on denim or chinos, where the belt looks entirely at home.

Waist sizes go from 80 to 115 cm in five-centimetre steps, so measure at the waist itself rather than guessing from another garment.