Lambretta Screw 5x40mm raised counter sunk, headset bottom, Series 3, stainless steel
MBFRCS5X40
Amongst many applications this fastener can specifically be used to secure a Lambretta headset top to the bottom headset (Series 3)
This is a cheaper version if you want the original look then use the MB made MBP0444.
£ 0.38
Price: £ 0.32 Ex Vat