The present invention comprises methods and compositions comprising Areca extract compositions and compositions comprising extracts of Ilex paraguariensis or theobromine. The electric connector includes a connection holding part configured to hold a connection state with another connector by each of a plurality of types of engagement. Once introduced to the flexible vessel, the enclosed pathway system thereby enables the fluid to be filtered and the filterable constituent examined with minimal complications of contamination of the sample through exposure to environmental pollutant external to the fluid sample. A communications module with a power supply and a relay operates to change the polarity of the d. The embodiments of the present invention can thus provide a balanced and compact operating mechanism that is ideally suited for rifles, carbines, and personal-defense weapons. A floor of the battery compartment is equipped with a roller conveyor.