The 0.120″ trimmer line is used to cut thicker grass and weeds. It’s larger in diameter and will increase the power and durability of the line, which leads to less breakage and wear-out. The edges of this square line are sharper than rounded trimmer line,and cut through the grass rather than tear at it.
NOTE: Be careful when using this type of line around any sensitive items in the yard which might be damaged by it such as trees, shrubs, wooden fences, etc.