Weedmat:

Ground Pins are recommended for pinning down and joining weed matting, securing bird netting and vege net to the ground.  They are made from High Density PolyEthylene and have full UV stability. Weedmat Ground Pins, Black, UV Stabilised HDPE

Abbreviations Used: 
m – metre m
mm – millimetre (0.001m) mm
g/m2 – grams per square metre
kPa – Kilo-Pascal, unit of pressure and stress – kPa a measure of force per unit area
HDPE – High Density Poly-Ethylene HDPE
TBA – to be ascertained; N/A – not applicable