Built with an advanced hybrid construction of water-resistant leather and FKM rubber, the Active Strap Pro is our most versatile band. We have combined the subtle contour of a modern leather strap with a high-performance FKM lining and ventilation channels to create a band that is as functional as it is stylish. Featuring water-resistant Heinen black leather from Germany, 100% waterproofing, FKM fluoroelastomer rubber coating, interior ventilation channels, and custom stainless steel hardware, this strap is designed for Apple Watch Series 6, SE, and all previous versions of Apple Watch. Measurements include a strap length of 81 mm on the buckle side and 118 mm on the adjustment side for 44mm / 42mm models. Compatible with Apple Watch 42mm, 44mm, and 45mm.