The Apple Watch Leather Loop band is comprised of leather-wrapped magnets. The band is sold in two sizes, Medium for 150–185 mm wrists and Large for 180–210 mm wrists. They are also available for both the 38/40 mm and 42/44 mm Apple Watch models.
The Leather Loop band was among Apple’s original band designs in 2015 and has been available in several colors, including Stone, Light Brown, Saddle Brown, Forest Green, Cosmos Blue, Cape Cod Blue, Bright Blue, Midnight Blue, Black, Charcoal Gray, Storm Gray, Smoke Gray, White, and Meyer Lemon.
Apple describes the Apple Watch Leather Loop band:
“The Venezia leather for this band is handcrafted in Arzignano, Italy. With an artisan heritage spanning five generations, the tannery has a history of partnership with some of the most prestigious names in fashion. A delicate milling and tumbling process enhances the beautiful pebbled texture. And magnets concealed within the soft, quilted leather allow you to simply wrap it around your wrist for a precise fit and a trim look.”
This is the band I purchased along with my original Stainless Steel Apple Watch, and it definitely shows some signs of wear. I like this style because it uses no mechanical fasteners that might potentially scratch a surface.