ProFractional utilises an erbium:YAG laser, which was chosen due to its high ablation efficiency. Erbium has a much higher absorption in the target chromophore water than CO2 which gives erbium the ability to vaporise tissue with very little thermal conduction. By contrast, due to their comparatively low absorption by water, CO2 lasers have lower ablation efficiency and therefore, unavoidably, conduct a significant amount of heat into the tissue.