Not that crap you get at HD, wallyworld or elsewhere, I bought me 100 foot length of 12/3 cabtire 600 volt capable wire, Damn, is it heavy but it makes the other crap look like tooth floss.
I got some great wire for 12 volt in 8 colors both 12 and 14 gauge gxl. Really nice stuff. I used it to make a new harness. Wire barn.com I believe. Good wire is hard to beat.