A    –     B       –     C       –    D    
Style – qty of spirals – qty of rods – rod gauge, spiral gauge
 
A.   Letter(s) indicating the Mesh Style you have, ie B(PB), RR(RSW), U(DB), IB
B.   Indicates spirals numbers per foot of width
C.   Indicates rods numbers per foot of length
D.   Indicates the wire gauge.  If it is four numbers (two pairs of numbers), the first is the gauge of the rods and the second is the gauge of the spiral wire.
 
For Example, B-8-8-6: B means the mesh is Balance type; the first 8 means there are 8 spirals pitch in one foot of width; the second 8 means there 8 rods pitch in one foot of length; the last number 6 means both the rod wire diameter and spiral wire diameter is 6gauge.