BT 4000 Twin Big Button Cordless Phones with Extra-Loud Volume & Call Blocking The BT 4000 Twin is a big button and hearing aid compatible duo set of landline cordless phones designed specifically for elderly users. Features include user-friendly design, which incorporates an easy to read amber backlit display with extra large font, bigger buttons, and amplify button for an instant boost in volume. The phones also benefits from BT’s nuisance call blocking, enabling users to prevent incoming calls from international and withheld numbers, in addition to blocking up to 10 specific numbers. A reliable choice if you’re looking for ease of use and dependable quality. User-friendly features Contacts can be stored on the BT 4000’s phonebook, which can store up to 100 names and numbers and only need to be entered once as they are automatically copied to both handsets. And in addition to the call blocking features, there is also a handy ‘Do not Disturb’ mode, which will silence the phone from ringing for all but the most important contacts saved in your phonebook. Extra loud & Hearing Aid Compatible Offering superb clarity of sound; the BT 4000 is a dependable choice of home phone for those whose hearing may not be what it used to. An integrated inductive coupler has been included for compatibility with hearing aids, and as mentioned previously there is an ‘Amplify’ button to give an added boost to the volume.