The Apple Watch Band 40mm (M/L) Sport Band in Midnight is a durable and lightweight strap made from high-performance fluoroelastomer material that offers a smooth, dense finish for comfort against the skin, featuring a flexible yet strong design ideal for everyday wear and workouts, along with a secure pin-and-tuck closure for a clean fit, and it is compatible with 38mm, 40mm, and 41mm Apple Watch models while providing a sleek, minimal look in a deep midnight black color.