To test the UC03-PRO I gathered various USB drives and a few transmitters to test function. Every wireless transmitter or Bluetooth receiver I tested in the UC03/04-PRO worked well without any latency issues. The UC03/UC04-PRO are perfectly sized. There were no issues with the size of the drives.
To give readers a good size comparison of the UC03 we snapped a shot an iPhone 6s+. iPhone plus models are all the same general size. The UC03/UC04-PRO seems perfectly sized to hold just about anything I pair it with. Both models support Apple Configurator application for managing multiple iOS devices.
If you use your laptop on the go the UC03-PRO or the UC04-PRO can turn your laptop into a pretty effective workstation. When working on the go you may need to use many forms of devices. The UC03/04-PRO can take the wear and tear and keep the USB ports on your laptop pristine. Some laptops only include one or two USB ports hindering overall work capability. A charging/data hub is a great way to increase efficiency.
To get an idea of how fast the UC03/UC04-PRO can charge devices I went with a direct comparison to a Samsung Fast Charging block.
The Galaxy Note 8 used for testing started at a charge of 47%. Plugging the phone into the dock shows an estimated time to full charge at one hour and twenty-six minutes. Plugging the phone into the Samsung Fast Charger shows an estimated time from 47% of one hour. The dock is a little slower than the fast charger, but still much faster than low-grade blocks.
Transferring a video file through the hub from a @7200rpm HDD we get a rate of just below 60MB/s.
Doing the same transfer from an NVME to the same USB drive with no hub shows the device is not hindering the transfer speed, at least in this environment.