There are a number of systems that are used to refer to the various weights of fiber. From thread to yarn to carpet fibers, various industries use different methods.

For domestic knitting machines, we often talk about 4.5mm or 9mm machines (standard and bulky gauge).

Industrial machines are referred to by GG (gauge).

In this context, gauge is the number of NEEDLES in one inch. Our standard gauge (4.5mm) machines fall into the 7 GG category.

Appropriate yarn for this gauge of machine is 4.5 Nm to 7 Nm.
1 Nm equals 1000 meters in one Kilogram(2.2 pounds).

Knit it Now uses yards per pound (YPP) to compare yarns. Below is a helpful chart that translates Nm counts to yards per pound.

Notice that a standard gauge machine is in the 2000 – 2500 YPP range.