The Apple Watch Sport Band was made from a flexible rubber material called fluoroelastomer with a metal pin closure. Sizes ranged from S/M, M/L, or L/XL. When purchasing an Apple Watch Sport Band, the S/M and M/L sizes are included in the box, allowing the band to fit wrists 140–210 mm.
Apple described the Apple Watch Sport band:
“Made from a custom high-performance fluoroelastomer, the Sport Band is durable and strong, yet surprisingly soft. The smooth, dense material drapes elegantly across your wrist and feels comfortable next to your skin. An innovative pin-and-tuck closure ensures a clean fit.”
This version of the Cocoa Apple Watch Sport Band includes a gold pin to match the gold Apple Watch models of the time. An alternate version of the band shipped with a silver pin.
This band did not come in Apple’s retail packaging. It was purchased from a website that sold Apple replacement parts and used Apple’s OEM packaging.
Source: Apple