Update, 6/23/16, 10:55am PT: After publishing the original article below, Razer CEO Min-Liang Tan reached out to me to disconfirm the Kaihua statement about the exclusivity of the Razer Green switch. I have now been informed that, as I previously wrote, there are still multiple manufacturers producing the Razer Green switch. Kaihua is one of them. Greetech is another. Razer would not state whether there are others.
I had previously suspected that Greetech was in the mix, but after my interaction with Tan, I sought to dig deeper. I removed a switch from a BlackWidow X Chroma to see if I could find any identifying information. Sure enough, there is a stamp under the switch that shows Greetech is this switch's manufacturer.
In summation: Although I had confirmation from Kaihua that it was the sole manufacturer of the Razer Green switch, that information was incorrect. There are still multiple manufacturers of the Razer Green switch, including (but possibly not limited to) Greetech.
A version of the original article is below, with heavy modifications to the copy and with the incorrect information redacted:
Razer is not simply rebranding Kailh switches. Manufacturers including Kaihua make switches to Razer’s specifications, and although the Razer Green switch is in many ways similar to the Kailh Blue switch, they are by no means identical.
In an earlier briefing, Razer mentioned in passing that it had built some of its own production lines and ostensibly improved on its Green switch. For example, it claimed to have boosted the lifespan of the switch to 80 million clicks. The company, however, has remained coy about what exactly that all means. We presume it has much to do with enhanced quality assurance measures.
Razer has not divulged precisely which of its keyboards will use the gussied-up version of the switch, but expect all of the new BlackWidow X keyboards (except of course the Cherry MX versions) to ship with them.