#30 is the twine gauge (larger is heavier) which measures 2.5mm
One strand of #30 twine has a (tensile) breaking strength of 216 lbs. and a knot breaking strength of 280 lbs.
100% Dupont Type 66-728 Knotted 3-Strand Black UV Treated/Bonded Nylon Netting
Typical uses for #30 x 1-3/4″ Mesh netting are: Baseball Batting Cages, Baseball Impact Netting, Softball, Soccer, Hockey Barrier (NOT impact), Football, Basketball Barrier, Debris, Aviary, and General Multi-Purpose Applications.