The ignition coil unit of a type used on IC engines has a housing of insulating material (1) that contains the coil and has a connection to a primary switch (6) that connects to a circuit board (8) and is contained within a chamber that is filled with a silicone gel material (12). An electrical connecting wire (21) passed from the gel and into an electrically insulating resin (14) within the housing. The wire has a formed flexible section (21a) within the gel and this absorbs any applied load caused by thermal shock. The wire connects with a pin (13b).
