Streamlined Feather-Line pre-preg carbon graphite extensions are light, feather-lite. As far as we know they are the lightest extensions in windsurfing. They have an incredible strength to weight ratio. Compare the weight to any other like extension. The 2 centimeter adjustment settings are set with a hard anodized aluminum collar tethered with a spectra line to a stainless steel pin. Fail-safe and virtually break proof . Finally we attach our new beefy ? super powerful 6:1 downhaul cleat with large diameter pulleys perpendicular for power, easy rigging and no crossed lines. A tough Dyneema super downhaul? line is included.