The invention relates to a cover (10) a holder opening (110) of a holder compartment (100) of an ID transmitter (200) particularly used for vehicles. The cover comprises a horizontally disposed cover portion (20) for at least partially covering the receiving opening (110) and at least two vertical latching portions (30) each having a latching surface (32) for latching engagement with a counter-locking surface (130) of the holder compartment (100), wherein at least one latching portion (30) serving as an unlocking-locking portion (30a) is designed to be movable relative to the cover portion (20)and is formed at least one latching portion (30) as a rigid latching section (30b), said rigid latching portion (30b) has a locking angle (alpha) between the locking surface (32) and the horizontal surface (H), which is formed as an acute angle.