That's pretty much what I use, expect that one is better than mine in a way because it has a piggyback 4-way - if you tow a simple trailer that needs the 4-way, you don't have to unplug this adapter from the original 4-way. That feature would be even more valuable if the 7-way were hardwired in.
I see that adapter seems to use all four wires of the 4-way, plus has four individual wires (one of which is white with a ring terminal. In this case, they seem to be connecting to the 4-way's negative ("ground") connection plus providing an additional wire for the same terminal. In my case, the adapter didn't connect to the 4-way's white wire at all, forcing me to make a separate connection. In both cases, the intent is to provide a negative connection with higher current capacity than the lightly wired 4-way, which is necessary to use the brakes
and/or charge line.