The Nomad Sport Strap is expertly molded from durable LSR silicone, known for its biocompatibility, antimicrobial and hypoallergenic properties, ensuring a soft, secure, and comfortable fit around your wrist. Key Features include waterproof silicone, hypoallergenic/biocompatible materials, and compatibility with Apple Watches 45mm, 44mm, 42mm. It's designed to fit Apple Watch Ultra & Ultra 2, Series 1-9, and previous SE. Salt mist test for 72 hours as per ASTM B117, ROHS compliant. Compatible with Apple Watch sizes 45mm, 49mm, 42mm, 44mm.