Roberto; as Joey said, neck taper is how much the neck widens over its length, and it is measured at the nut and the 24th fret. And as Joey said, there are two standard tapers, the classic and the comfort, and then there are custom tapers. Classic taper for a five string is 2.0 at the nut and 2.5 at the 24th fret. Comfort taper for a five string is 1.875 at the nut and 2.930 at the 24th fret. Classic taper was the standard through the 70's and 80's, and is thus found on Series I and II, and on Persuader, Spoiler, Elan, and Distillate models. In response to the growing popularity of slapping, in the 90's the Comfort taper was introduced on the new Essence, Rogue, Europa, Epic, Excel, and Orion models. Signature models traditionally have had Classic tapers; however, with the advent of the Balance K bodies, many now have Comfort tapers. And then there have always been Custom ordered tapers.