Water Proof 300-75 Ohms Matching Transformer with F Socket/Connector is manufactured by MDR Electronics. MDR Electronics is an ISO 9001:2008 and ISO 14001:2008 accredited organization. The Water Proof 300-75 Ohms Matching Transformer with F Socket/Connector is used as impedance matching device for the TV. This adaptor is water proof. The other range of products manufactured by MDR Electronics is Electronic & Computer/Laptop Accessories, Audio/Video, Pro-Audio Cables, Connectors & Cords, Cable Organizers, Cable TV Series and Fiber Optic Series. This 300-75 Ohms Matching Transformer is use to convert the 300 ohm twin lead wire to a 75 ohm "F" type connector.