One digit is 190mm long, 110mm wide and depending on what connection cables you use about 12-15mm high and you can combine as many of them as you want. The only limit is the memory of your microcontroller and the refreshrate you want to achieve.

I combined four of them as you can see on the pictures.

It is designed to fit 7 "8 Pixel WS2812b Led-boards" (1 per segment) and therefore can display every color you like and you can break down animations to a single pixel.

I sourced them from aliexpress. The link below links to an offer of 10 pieces, feel free to compare prices and find other boards. They are available on black and white pcb's and keep in mind that it is never wrong to have some spare parts ;) 10pcs 8 channel WS2812 5050 RGB LED board