A filler cap for a tank

The sealing cap for a tank filler neck has a retaining band(4) connected to the housing or cap wall(1c) without the use of an independent fastening element. The fastening of the retaining band on the cap wall is by way of a slot and protrusion connection. A circular fitting hole is formed in the wall of the cap, the edge of which form the protrusion of the slot and protrusion connection, and into which fits the retaining band by a plug-in section(4a) provided with an annular slot.