A pressure equalization apparatus can include separate longitudinal bores which form a continuous flowpath, the flowpath alternating direction between the bores, and the bores being interconnected at opposite ends thereof. A signal containing information about the image is transmitted to a remote central station. An etchant of the present invention may be used to etch desired areas in the BPSG layer, wherein the high selectivity for BPSG to TEOS of etchant would result in the TEOS layer acting as an etch stop. The wet reagent includes from about 0. The barrel extender is inserted into the barrel extender opening and to the butt where it is secured to the gun stock with a barrel extender bolt.