A method for synchronizing ovulation in sows and gilts by a single injection of hormones is disclosed. According to one embodiment, the first output stage operates when the Class-ABB amplifier is in a quiescent state and the second output stage operates when the Class-ABB amplifier is in an active state. A search option is ensured by the provision of an attribute search unit. In some embodiments, the connector piece is a link configured to be receive the belt and to move along the belt. The unresolved dependency may be based-on data that must be restored or created prior to completing restoration. Mounting clips integrally carried on the cover snap into and fix the window in the cover aperture.