Marinco  (1PCMRV 30 Amp Male to 30 Amp Female RV Locking Adapter 30A 125V 2-pole, 3-wire RV use only (male plug) to 30A 125V locking (female side) Pigtail Adapter Allows the connection of standard RV cordsets to various electrical receptacles or cords that have a dissimilar power configuration Includes threaded and easy lock ring