Compatible Models : The sport silicone loop bands are compatible with WHOOP 4.0 and 3.0 (Note: Whoop Fitness Tracking Not Included) Soft, Breathable & Lightweight : Our for whoop 4.0 strap is made of ultra soft silicone,skin-friendly,flexible, sweat-resistant, water-proof, breathable,lightweight and durable. with skin-friend metal buckle give your wrists a comfortable silky touch of milk, prevents skin from irritation; which feels comfortable next to your skin, Our whoop 4.0 strap for women men perfect fits vacation,sport,daily,date or sleep. Adjustable Size Design : The whoop bands are designed with sturdy hook & loop fasteners, easy to adjust the band to fit your wrist and wearing firmly. Silicone fashion design fit for all stylish women and men.