Phone Serene Hndst CL-65Serene CL 65 Additional Handset. The CL 65 is expandable up to a total of 5 handsets. Additional handset bases do not require being plugged into a phone line jack. The charging base merely plugs into an electrical outlet and the handset works from the main base phone to which it is married connected. This is great for use in rooms which do not have a telephone jack.