A compound of the formula, , or whereinZ, A, B, C, R, R1, R2, Q, and n are as described herein. The apparatus has a primary chamber containing a predetermined agent separated from the labeling portion. When the kensington lock is inserted into the first kensington slot, this event is transmitted to inhibit the release of the engagement of the mounted portable computer, to enable its removal and to restrict the exchange of a PC card relative to the docking unit. to obtain a highly flexible, high strength material, and printing or painting the required advertising motifs thereon. The compensator assembly utilizes a configuration of at least one spring disposed between two pistons so as to reduce the use of elastomer seals to thereby reduce a slip stick effect.