These connectors are very common in the off grid solar world, and now you can have an extension cable to connect your device to your generator without having to have the generator right up close.
 
50A high current Anderson style plug extension lead
Made with high quality 8AWG tinned copper wire 
 
Available in 5 different sizes from 1.5m to 15m:
P3510:  1.5m
P3511:  3.0m
P3512:  5.0m
P3513:  10m
P3514:  15m