A topical insecticide preparation is provided which can be safe to use and avoids many common deleterious side effects of conventional topical insecticides. The units are browser enabled HTML files and include special links to at least one of the other publications units. Multiple channels of noise reduction can be implemented with separated threshold controls and with low level expansion and dynamic filtering being combined so as to detect and track the input level and dynamic range of the guitar directly. Even further, at least said frame or said holding device comprises an at least partly tapered shape, and elastic means such as spring means forcing said holding device against said frame and thereby said locking elements against each other.