The great benefit of Square is that it can be used across devices, however the hardware is designed specifically for payments on the run due to its compatibility with smartphones and tablets.
The magstripe reader connects directly into the audio jack or lightning port of a smartphone or tablet, while the contactless reader connects to those devices using low energy Bluetooth technology.
A more comprehensive list of compatible mobile devices is available
here.
Limitless card readers are available at an additional cost, enabling large numbers of staff to take payments on your behalf. Compatible hardware like receipt printers, barcode scanners and cash drawers can also be connected.
Most functions are available via the smartphone or tablet app, but advanced functions are housed within the online dashboard available on PCs or laptops.