Sometimes a blue buffer tube is used on the fiber instead.[22] Hardened Fiber Optic Connectors (HFOCs) and Hardened Fiber Optic Adapters (HFOAs) are passive telecommunications components used in an outside plant environment. They provide drop connections to customers from fiber distribution networks. These components may be provided in pedestal closures,[note 1][23] aerial and buried closures and terminals, or equipment located at customer premises such as a Fiber Distribution Hub (FDH) or an optical network terminal unit.