BT Graphite 1100 has energy efficient power supplies that (according to BT) cuts energy use by 30%. Available with up to 5 handsets & offering remarkable value the Graphite has caller id & call waiting (BT line only). 50 name & number phonebook plus missed call log also feature. If you have multiple handsets you can call transfer & have 3 way conference calls also (handsets can be muted also).