A Bridge Device is a small helper application (installed on a computer at the retail location) that connects to your real receipt printers and relays print jobs from Sprwt to them. Because a web browser can't talk directly to most receipt/thermal printers, the Bridge polls Sprwt for pending print jobs, prints them, and reports back which printers it can see — this is what lets a POS Device print an Order Receipt or Meals Receipt to a real networked/USB printer instead of using the browser's print dialog.