The KX-TGP550 has all the features and benefits of the KX-TGP500 and adds a corded base unit with a large white backlit LCD and 5 hours Talk Time 5 days Standby plus a Hands-Free Speaker phone Handset Call Button on the base unit and one-touch call transfer with Busy Lamp Indication. The KX-TGP500 is expandable up to 6 DECT 6.0 cordless handsets and supports up to 8 phone numbers and 3 simultaneous calls. It boasts Wide Band Audio (G.722) and 5 hours Talk Time 5 days Standby. Its elegant design features a white backlit large LCD on the handset and a handset Call Button on the base unit. It also has a handset speakerphone 2.5mm headset jack and belt clip.