The Apple Watch Nike Sport Loop band is woven from nylon thread to create a hook-and-loop closure. The Nike Sport Loop bands differ from the Apple Sport Loop versions in that they are made to match current Nike running shoe styles and contain reflective thread. They are available for the 38/40 mm and 42/44 mm Apple Watch models, but so far have only been offered in Regular size to fit 130–190 mm wrists.
The Apple Watch Nike Sport Loop band has been available in several styles, including Bright Crimson/Black, Pearl Pink, Smokey Mauve, Midnight Fog, Celestial Teal, Olive Flak, Cargo Khaki, Black/Pure Platinum, Black, Summit White, Desert Sand/Volt, Pink Blast/True Berry, Royal Pulse/Lava Glow, Summit White, and Black. Close inspection of the Sport Loop reveals that each style is comprised of a base color and at least one additional accent color. For example, the Black style uses a combination of black, white, and gray thread colors.
Apple describes the Apple Watch Nike Sport Loop band:
“Soft, breathable, and lightweight, the Nike Sport Loop is designed for fitness, with select colors matched to the new line of Nike running shoes. It features a nylon weave with reflective thread designed to shimmer when light strikes it. A hook-and-loop fastener makes for quick and easy adjustment, and dense loops on the skin side provide soft cushioning while allowing moisture to escape. On the reverse side, the attachment loops are securely anchored for superior durability.”
This Bright Crimson/Black model shipped along with an Apple+Nike Aluminum Series 3 Apple Watch. This was the first Sport Loop Apple Watch band I owned, and I have found this style to be my favorite.
Source: Apple