The byron smartwares by201 portable wireless chime kit has a 100 metre operating distance it provides a choice of six melodies and has volume control it features self learning codes and will keep the code even when the batteries run out and are replaced the battery powered portable chime can be taken anywhere within the operating range the chime can have up to 2 bell pushes controlling it it has an 80 85d b rating depending on the sound compatible with all byron b ranges features a flashing ligh