Austin, Texas-based CoinTerra has announced its second product.

Called the GSX I, the card form factor bitcoin miner uses water for cooling, and notably, has a radiator serving as a heat exchange for the water, piping it over the board. The GSX I is a 400 GH/s unit that has a 28nm chip.

Jim O’Connor, vice president of engineering for CoinTerra, spoke to CoinDesk about the upcoming launch, and said he believes using water is the best method of cooling for a card.

Said O'Connor:

“With the PCIe form factor and space constraints of a PC case, there simply is no other solution that is able to dissipate heat effectively enough.

Mounting any form of air cooling head on the ASIC would make it impossible to fit the card in any standard motherboard and not take up more than two PCIe slots"

O’Conner believes that the card will allow for increased mining flexibility.

“The GSX I is designed to facilitate daisy chaining via USB using a PC host, but we will ultimately leave it up to the community to experiment with their own flavors of controller,” he said.

CoinTerra stated that, through testing, it has found that a single BeagleBoard host could control at least 20 cards.

“Our simulations show that a single BeagleBone Black should be able to provide work to a large number of GSX I cards,” said O’Connor.

A BeagleBone Black is a $45 device powered by a 1 GHz ARM Cortex-A8.

CoinTerra isn’t the only mining company developing water-cooled PCI cards.

Kansas City-based Butterfly Labs also has a similar product on the way. Called the Monarch, that unit is a 600 GH/s 350 watt card for $2,196. By comparison, the GSX I consumes 400 watts of power and costs $1,599.

The Monarch is expected to start shipping this month. It will be available in air or water-cooled configurations.

Josh Zerlan, VP of product for Butterfly Labs, recently told CoinDesk that radiator mounting is one challenge for water board cooling.

O’Conner says that CoinTerra’s GSX I will fit within a standardized specification.

“The radiator is designed for easy mounting using standard 120mm fan mounts available in most standard PC cases,” he said.

CoinTerra plans to ship the GSX I by June. The company has received some criticism for not shipping its first product, the $5,999 2 TH/s TerraMiner, on time.

In a statement to CoinDesk last week, CoinTerra addressed the situation. The company wrote that units are being delivered, and that it is trying to ramp up operation.

Preorders for the GSX I are open now. The scheduled date for shipments is June 2014.