A polishing disk for a tool for the fine machining of optically active surfaces on spectacle lenses in particular is disclosed, which comprises a support body, to which a foam layer is attached, wherein a polishing film bears against the foam layer. This prevents the ball from directly contacting the inner surface of a pipe housing socket. The digital timer, after it is switched on, counts periodic counting pulses which are derived from the clock signal, in order to signal the end of the waiting time as soon as it has counted a desired number of these pulses. A measurement circuit is configured to determine a resistive-capacitive time constant of the oscillator by determining a mean of the first and second periods. Furthermore, an associated smoking cessation kit and weight management kit is also provided. The drive includes a loading device for transport of a storage disc into the drive, the loading device including a carrier for accommodating the storage disc.