It's not the first Ethereum mining ASIC. Also, that isn't so much a single ASIC as a box with a bunch of ASICs in it.
The problem is that Ethereum is designed to be sufficiently ASIC-resistant that buying the box full of ASICs costs about the same for a given hash rate as buying a bunch of video cards, at least if you could get them at the prices from a year ago. For something more ASIC-friendly, you might be able to get a given hash rate from ASICs for something like 2% or 5% of the cost of buying video cards. So it's not impossible to make an ASIC for Ethereum; it just doesn't give the huge gains that a Bitcoin ASIC would.
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The problem is that Ethereum is designed to be sufficiently ASIC-resistant that buying the box full of ASICs costs about the same for a given hash rate as buying a bunch of video cards, at least if you could get them at the prices from a year ago. For something more ASIC-friendly, you might be able to get a given hash rate from ASICs for something like 2% or 5% of the cost of buying video cards. So it's not impossible to make an ASIC for Ethereum; it just doesn't give the huge gains that a Bitcoin ASIC would.