A radiopaque marker may include a body formed of a polymer and being adapted to be disposed around a portion of an implantable medical lead and a symbol formed of at least a radiologically dense powder or liquid added to the body and designed to identify the implantable medical lead as being safe application of a medical procedure. A semiconductor die has an active surface and bumps formed over the active surface. This configuration makes it possible to omit or to reduce the use of axial bellows on the set of busbars, thereby reducing the cost of manufacturing the metal-clad substation. The gas generator includes a guiding element for guiding the gas flow to a lower volume generally located below a lower surface of the projection system and to a volume between the lower surface and the substrate. Both the first threaded fastener and the second threaded fastener are threaded into the base, wherein the roundness of the first threaded fastener and the roundness of the second threaded fastener are different.