I have a mexican fender jazz bass from either 1999 or 2000. The strings that came on it have black windings on both ends. I was wondering if anyone knew what these strings are. Are they fender's own strings? also how do i know if they are nickel or not. they definately feel and sound smoother than any other steel string I've ever played. On electric bass i have always just used rotosound steel strings, but i like the feel and sound of these better. I feel like the rotosound have always had a thin sound with out enough of a warm round sound especially on my other bass which is a fretless. can any one help?