A grommet includes a small tubular section, an enlarging tubular section continued from an end of the smaller tubular section, and an annular recess on an outer surface at a large diameter end of the enlarging tubular section. The laser source is assembled andor embedded within the explosive charge. In the second position the sheet material is provided with upward support to support the predetermined shape to be cut from the sheet material and wherein in the second position the or another support means includes a through cut commensurate to the line or lines to define the remaining perimeter of the predetermined shape.