 Each sphere, called a "digital optical module" (DOM), is about in diameter, contains 31 photomultiplier tubes with supporting electronics, and is connected to shore via a high-bandwidth optical network.Together, the ARCA and ORCA detector contain 6210 DOMs.At the shore of each KM3NeT installation site, a farm of computers will perform the first data filter in the search for the signal of cosmic neutrinos, prior to streaming the data to a central KM3NeT data centre for storage and further analysis by the KM3NeT scientists.