Stretchable yarn interwoven with silicone threads designed for ultracomfort with no buckles or clasps. footnote ¹ Flaws although not dealbreakers: The Mustang has only 8 holes for adjusting (a smaller vary than on many other bands we examined), and silver is the sole coloration option for the components. Apple Watch https://allhealthmarket.com/product/aeahmarket/appleband/silicone-strap-for-apple-watch/apple-watch-slim-band-compatible-with-41mm-40mm-38mm-42mm-44mm-45mm-iwatch-strap-for-se-series-7-6-5-4-3-2-1-for-women-men/