๐ NEMA 6-15/20R, 15/20 Amp, 250 Volt, 3-Prong Female Connector. ๐ NEMA L14-20P, 20 Amp, 125/250 Volt, 4-Prong Locking Male Plug. 20A 4-Prong Generator Plug. NEMA L14-20P. NEMA 6-20R. Heavy-duty, compact locking adapter converting a 20 Amp, 125/250 Volt L14-20P plug to a 15/20 Amp, 250 Volt T-blade female connector.