Taillight bulb. 12 volt 5 watt 21/3 CP (15mm or 0.6 base).
Fits:
VNX Vespa P125X 78 - 81 P Series 125cc
VLX Vespa PX150E 81 - 06 PX 150cc
LML LML Star / Stella 150cc PX 150cc
VSX Vespa P200E 77 - 82 P Series 200cc
You can look up your model in this bulb chart.
