I bought this Amazon one as a direct replacement (white, 6 ft). The only thing to note is that it's not the super rubbery feel of the original. I'm not sure you can even find something like that aftermarket, but this is an excellent cheap option.

I eventually upgraded to this for something a bit more robust and better-feeling. TBH, I got it because of the relatively rare 4' length of the shorter one, and the longer one just happened to feel just as robust to be my primary carry for PB now.