a cell phone with big buttons and large color displays.

[sitifan]

1. To meet the unique needs of the elderly, the company designed a cell phone specifically for seniors, which has big buttons and a large color display.
2. To meet the unique needs of the elderly, the company designed the cell phones specifically for seniors, which have big buttons and large color displays.
3. To meet the unique needs of the elderly, the company designed a cell phone specifically for seniors, which has big buttons and large color displays.
Source: https://classic-blog.udn.com/chihchien180/14740056

According to the above link, #1 and #2 are correct; #3 is incorrect.
But some Taiwanese teachers of English think #3 is also correct.
Is #3 acceptable to native speakers?

 

[teechar]

Can one cellphone (mobile phone in non-AmE) have several colour displays? If it can, then #3 is okay.

 

[Tarheel]

All of them say the seniors have big buttons and large color displays. In my humble opinion, there was some very sloppy editing. Try:

The company designed a cell phone especially for older people. It has big buttons and large color displays.

I guess I'm going to have to look up "color display".

 

[sitifan]

I guess I'm going to have to look up "color display".

A display monitor capable of displaying many colors.

 

[Tarheel]

A display monitor capable of displaying many colors.

Yep..I learned what a display monitor is too. (We used to just call it a computer monitor.)