Everything on Amazon is third party. At least in regard to Gekko Science product.
I think the user is asking about a PSU and what one would be recommended - as they ordered a r606 without the PSU. I personally would have bought the package that came with the PSU.
The link below, I believe, is the re-seller listed by Sidehack - the PSU that comes with it can power 7-10 r606's - depending in whether you go 120v/240v
MinerSupply on Amazon.com (forum user Rockmoney)
https://www.amazon.com/GekkoScience-R606-Terminus-Bitcoin-Consumption/dp/B07RPZTFN7