Abstract: A reversible flat key for cylinder locks, having lead-in bevels at the tip of the key, and with double rows of recesses for arranging the tumbler pins in proper order, arranged on each wide side of the key, wherein the double row of recesses on one wide side of the key is arranged offset in the transverse direction relative to the double row of recesses on the opposite wide side of the key, and the lead-in bevels are arranged off set relative to one another, the bevels being formed respectively as individual grooves extending over the longitudinal center plane of the key.