This power cord safely allows the transfer of power from a straight-blade 50-Amp, 125/250-Volt outlet (NEMA 14-50R) to a locking style 50-Amp 125/250-Volt inlet (NEMA SS2-50P, CS6365). This product is designed with RV applications in mind, including a jacket rating of STW for extra heavy-duty usage.
https://www.amazon.com/Conntek-14455-15-Power-Cord-Locking/dp/B0034U9IEM