The invention relates to a method for locking a gun that includes a firing pin and a lock cylinder provided with a lock cylinder bracket. According to one embodiment, stabilizers are removably attached to a cutting guide to temporarily lengthen the surface against which a saw or other cutting device rests. The cell solid electrolyte membrane is preferably fabricated from Nafion. The dumping resistors are connected to at least one of the power supply terminal, output terminal, and automatic frequency control voltage input terminal. The optical absorption coefficient of the sample is quantified from spectra of the measured photoacoustic signals. The processor is configured to selectively power the at least one peripheral device port when the processor is in a sleep state according to at least one setting stored by firmware of the processor.