1987 Philips #12342 H4 12V 55/60W

The model #12342 tungsten-halogen lamp shown here is a pre-production sample that was used for testing purposes (vibration resistance, light distribution, etc). It was made at a time when Philips changed the filament mounting structure of its standard H4 headlight lamps, phasing out an earlier design featuring a transversal quartz rod support fused to the bulb, a construction kept a while longer for heavy-duty lamps (see there). In the new design this glass support is held by all three lead wires, one of which is tilted in order to provide some additional stiffness to the overall filament-holding structure. Because this is not a full production model, this lamp lacks the usual iron silicate coat at the bulb extremity, which normally blocks off any stray light emitted along the lamp axis.