This particular model is built to be used by left-handed people. Children, or adults with smaller hands, might find that this mouse works well for them.
From Amazon
R-Go HE Mouse - Ergonomic Mouse - Large (Hand Size above 185mm) - Left Handed - Wired
Conrad Electronic
R-GO Tools HE (RGOHELELA) Ergonomic mouse USB Size: L Black/silver 5 Buttons 500 dpi, 1500 dpi, 2000 dpi, 3500 dpi Ergonomic