Here's what they say about them on their website -
"This set features a warm, deep-forceful timbre, suitable for various instruments and playing style, for bowing or plucking.
• For various instruments and playing style, concert strings
• Braided stainless steel core, Ni-Cr winding.
• Suitable for：
A1006(4) 4-string 3/4 double basses (more sizes available upon order)
A1006(5) 5-string 3/4 double basses (more sizes available upon order)"
Set part number A1006 (4) Braided steel core with Nickel Chromium wound.
The colour codes are:-
Tailpiece ends are Black
Peg ends are E (4th) = Crymson to Black with a silver twist thread - this is what you are buying on this listing only the E (4th) string as a single separate string.
A (3rd) = Crymson start to Emerald with a silver twist thread
D (2nd) = Crymson start to Azure and a silver twisted thread
G (1st) = Crymson start to Violet with a silver twisted thread
This is a four string set
The above strings are also available as single strings, very limited quantity but available as this listing is posted so see my separately priced listing. (E - 4th)