For Fitbit Versa 3/Sense Bi-color Silicone Smart Watch Strap – Black / Grey Two tone design, modern outlook. Soft silicone material with holes, fast heat-dissipation, comfortable to wear. Safe and eco-friendly material, no harm for body. The size can be adjusted according to the circumstance of individual wrist. • Material: silicone • Width: 23.2mm • Length: 9.3 + 13.5cm • Dial size: 41mm Size: 115-200mm (Without watch)