OptiPower Lock Straps strong and secure, they feature a revolutionary non-slip coating on the inside surface that securely locks your battery in place, preventing them from shifting, even during the most extreme 3D aerobatic manoeuvres. These straps come in five different sizes, with the straps featuring a tough plastic buckle and a strong Velcro closure for maximum holding power and security. Each package contains 1 OptiPower Lock Strap.