Stone Island first started using ART numbers in 1986 to help verify genuine pieces.
The ART number identifies the year, season, brand, product type, material, colour and treatment process and will be found on the product label.
The first two digits indicate the year and season the product was made. Odd numbers represent autumn/winter collections, even numbers, spring/summer.
The next two digits show which brand the product belongs too. 15 is Stone Island, 16 Stone Island Junior, 14 Stone Island Denim, 18 CP Company and 25 Stone Island Limited Editions.
The fifth digit indicates the product type, for example 1 means shirts.
The final digits in the ART code refer to the material, the colour and the treatment process.