Abstract: A block for enclosing, holding or connecting in a signalling pyrotecnical network exploding pyrotecnic ignition devices, such as cords or detonators. The block comprises, in sequence from a centrally arranged ignition device (9), an inner wall (2) substantially surrounding at least an axial part of the ignition device, an empty space (7), or a material of lower density than in the inner wall, substantially surrounding the inner wall, an outer wall (1) substantially surrounding the inner wall and the space and fixation means (6, 8, 12) for keeping the ignition device, the walls and space in said positions. The block may have an annular inner space (65) or channel spaces between the ignition device and the inner wall and fixation means (35,66,69) for keeping the ignition device, the walls and space in the stated positions, whereby the inner wall is axially slitted (33,64).