A sealing tool for a tray sealing machine, comprising an upper tool and a lower tool with a main body having a tray depression for receiving at least a part of a tray to be sealed, and a tray carrier, wherein a gas channel runs through the tray carrier. The sealing tool is characterized in that the tray carrier comprises a first plate with a first pressing surface and a second plate with a second pressing surface and the first plate has a first depression which extends from the first pressing surface, wherein the first depression forms at least a section of the gas channel when the first plate and the second plate are pressed against each other at the first and the second pressing surface, respectively.