Fits Apple watch size 38mm (Series 1,2,3), 40mm (Series 4,5,6,SE), 41mm (Series 7)
Fits Apple watch size 42mm (Series 1,2,3), 44mm (Series 4,5,6,SE), 45mm (Series 7,8), 49mm (Ultra)

Made from silky high strength seat belt nylon webbing 
Comfortable and luxurious wear
Stitched construction 
Length: 80mm and 135mm
Strap thickness: 2.5mm         
10 Laser cut holes
High-quality stainless steel hardware

Video tutorial on how to change the strap for Apple Watch can be found