The GU-1 Optical Closure developed by Optotec is an in-line environmentally sealed closure designed for use in a wide range of optical installations with medium/low capacity cables. Molded in reinforced fiberglass special resin, GU1 closure is suitable ether buried or in cable ducts with manholes. Four optical cable entries/exits are made by means of special calibrated gaskets. They can house cables with different diameters and can be used as many times as necessary. Additional cable entries are available on both sides and the gaskets can manage more than one cable. Such system considerably simplifies the operations needed for the ingoing/outgoing cable in order to assure a perfect moisture proof without use of flames, air heaters or putty.