This cutter blade (60) for a lawn mower (10B) is provided with an upper blade (60A) and a lower blade (60B). The upper blade (60A) comprises an upper blade base (64) and an upper outer end (66) positioned above and further radially outward than the upper blade base (64). The lower blade (60B) comprises a lower blade base (76) and a mowing section (78) positioned below and further radially outward than the lower blade base (76). The upper blade base (64) overlaps the lower blade base (76).
