For those without a 30 amp receptacle built into your generator, there's an 'adapter' that doubles the contact surfaces of the duplex outlet (if you build your own redneck special).
And, for you flamers, it's not a death-cord if you have more brains than a sweet-pea when using it. Flame away, but its better than anything you can buy, short of a Companion or other generator that comes with a proper receptacle for your trailer's power cord.