Four adapters that let plugs from elsewhere meet a US socket, covering the awkward direction most sets forget: you have the device, the hotel has the wrong hole. Between them they handle UK, European and Indian plug shapes, and the range extends to over 150 countries.
Round European pins convert to flat US-style blades and the reverse also works, so one small handful replaces a drawer of single-country adapters. The prong arrangement seats firmly, which keeps a charger from sagging out of a loose hotel socket halfway through the night.
Four in the pack means one for the room, one for the bag, and spares for whoever forgot theirs. Before plugging anything in, check that your device is rated for the local mains voltage.
