It's not mono, it's not braid and it's not fluorocarbon, Berkley engineers have named it Nano in it's own category "Uni-Filament"
Nano is fused using a heat process that binds over 300 fibres together - most manufacturers would use glue - however with Berkleys patented process these fibres will not come apart like most others. To sum up , Nano casts further with less effort; lures will run deeper because Nano is so thin that there is no resistance or drag hindering the sink rate.
Its smooth outer means that it is highly abrasion resistant and the recommended knot for ultimate strength, is the double Palomar!
For joining to fluoro or mono leaders Berkely recommends the Allbright double.
Minimum diameter but with superior strength
Direct contact to lures and bait
Immediate hook sets and zero stretch
25-30% further casting ability with no more effort