Phys.org's ESA's next satellite propelled by butane describes GomX-4B's butane powered cold gas thrusters, and how it will test them and use them to navigate to different distances from its partner GomX-4A. See Gunter's Space Page. Also see ESA.
The image below is shown in the article. If I understand correctly this represents one sixth of the 6U spacecraft - or 2x0.5 U at one end. It's said that there are four thrusters, and one pair will be used primarily with the other pair as backup.
Where will the thrusters be located? Can they vector, or are they fixed wrt the spacecraft's center of mass? How will the spacecraft ensure controlled, directed thrust without picking up spin around any axis, using only two fixed thrusters? Are there reaction wheels for this, and other types of thrusters for unloading of accumulated angular momentum?
below: "Thruster chip for the GomX-4B CubeSat’s propulsion system, designed by Nanospace in Sweden. Elements such as flow channels and sensors, chamber and nozzle are fitted into a 1x2 cm chip, just 1 mm thick by using microelectromechanical systems technology, otherwise known as MEMS. In terrestrial terms, MEMS is already a very mature technology platform: there are such devices all around us, in our cellphones, watches and cars." From ESA here
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below: Cropped and reduced from here. Open in new window for larger size.
GomX-4B’s cold-gas thruster system takes up two half-CubeSat units at one side of the nanosatellite, with two spherical titanium tanks filled with liquid butane. It has four 1 mN thrusters, typically to be fired in pairs while keeping one set in reserve. Credit: Nanospace