Here is the best place to get them in the US.
https://www.112bit.com/I hope this helps.
They are the number one Bitmain distributor. I have and do use them for my purchases of Bitmain and now ASICMiner products.
I have one S1. I'm not ordering two upgrade kits because of Bitmain's MOQ.
Anyone have any spare they have because of the MOQ?
Reputable sellers preferred.
Scammers need not apply.
Thanks.
M