Apple Watch Ultra is also compatible with 45mm bands, but 45mm bands should really only be worn for informal, each day wear. Stretchable yarn that’s interwoven with silicone threads and designed for convenience, with no buckles or clasps. footnote ¹ Anneke Knot is a full-time vogue and beauty freelance writer. https://allhealthmarket.com/product/aeahmarket/appleband/silicone-strap-for-apple-watch/soft-silicone-strap-for-apple-watch-band-ultra-49mm-45mm-41mm-44mm-40mm-42mm-38mm-sport-watchband-iwatch-bracelet-series-8-7-6-5/