Abstract: A grate bar for combustion systems, having a substantially closed surface facing the combustion side, a rear support region designed to be placed on a grate carrier for forming the grate, and a front nose region, which is rounded between the surface and front edge and has a bearing surface designed on the lower face and further has cooling fins for air cooling which protrude from the lower face of the surface forming the grate. A head part in the interior has at least regionally thickened head fins for air cooling in the longitudinal direction and vertical direction below the surface facing the combustion side. The grate bar can also be a reversible grate bar.