100 Pieces Netzerkoz 4x40 Chipboard Screw All products in the package and are guaranteed.Din 7505 Chipboard Screw is used for comfortable and undamaged assembly in many kinds of materials such as MDF, soft and hard wood types. Thanks to its deep thread structure and pointed tip, it can be applied to the material without any pre-drilling process. Screws are star countersunk head.