Special tool for pre-drilling wooden stair treads in conjunction with the fischer stair tread fastening TB or TBB. Advantages: The elastic shaft geometry allows for the absorption of vibrations, prevents creaking noises, and thus increases comfort. The stair tread fastening for steel substructures (TB) requires only a very small cavity due to the short expansion element, making it suitable for slim steel profiles. Applications: Wood treads building materials TB for fastening in: steel profiles TBB for fastening in: solid concrete materials. Functionality: The plastic expansion anchors are suitable for anchoring wooden treads and wooden panels over 30 mm on steel profiles (TB) or in solid materials (TBB). Optimal holding forces are only achieved when the fastener is glued with cold glue into the wooden tread. The plastic washers included with the TBB allow for leveling unevenness of the substrate.