A chuck for use with a manual or powered driver that may also be used for hammer drilling. A reliable and high-strength connection to the foam material is achieved due to the fact that the connecting elements consist of an adhesive medium, especially a fluorine gas, applied at least on the other side of the adhesive closing part. The off-axis orientation of the edge surface provides an additional variable for controlling the etch rate during the ELO process- and therefore the etch front may be modulated to prevent the formation of high stress points which reduces or prevents stressing and cracking the epitaxial film stack. The private key may then be used to decrypt any encrypted messages received. The apparatus includes a detector that detects a current applied to a motor, a controller that outputs a control signal based on the detected current and a switch that varies the number of windings of the linear motor coil on the basis of the control signal.