Appreciation goes out to
for encouraging me to try strings.
Fleet Ultimax Turbo Nano 66 sounds a bit like BG66UM but the play is MUCH different. The diameter reading is accurate- it sounds a half step sharper than ZM67 at the same tension. The Nano 66 string has a wonderful thinness that gives a feeling of great sensitivity and control, while not being rough. It leans on being slippery, but it's rough in a way that doesn't show on the surface of the string. That is, when I look at or touch the string, it isn't rough.
Like lots of other slippery strings, it offers lots of power, but not as much as BG66UM. The power is just around BG80, give or take. The focus of this string is supposed to be control.
Control at the net with netdrops is good especially because of its thinness, and spinning netdrops are a pleasure. Shot placement is really easy with this string and control seems to be spot on.
The durability is good- minimal fraying after a month's play (22x24, ~10 hours per week). I haven't tried NBG99 so I can't really compare- sorry.
I have tried both of this. NBG99 better. but NBG99 weight heavier. You can feel slightly head heavier if you strung NBG99 on your racket. not recommend NBG99 string on head heavy racket, will even heavier weight on your racket.