A ball grid array ceramic filter including a substrate having a ground layer of conductive material disposed over one of the surfaces thereof and a plurality of strips of conductive material on the other of the substrate surfaces defining resonators adapted to receive and pass RF signals. An indication of a hazardous condition within the underground environment can be identified from the acceleration information collected over a period of time. This linear torch is particularly suitable for photoresist etching and processes in which it has the advantages of high chemical isotropic etch rate and low plasma damage. Die eye boxes and die eye points are set on specific patterns of a die and it is determined whether or not the die is mounted in an exact second position. Further, each dilation member is tubular and is flexibly biased toward a substantially cylindrical configuration.