This was my late mother's, bought new specifically because it is extra loud and has large buttons.
Geemarc CL100 Big Button Corded Phone Hearing Aid Compatible White
Geemarc CL100 Big Button Corded Telephone - white - boxed, no instructions
Geemarc CL100 - Big Button Corded Telephone with Loud Receiving Volume and One-
Geemarc CL100 Big Button Corded Telephone with Loud Receiving Volume and One...
Geemarc CL100 - Big Button Corded Telephone with Loud Receiving Volume and...