This carb rubber is 40mm ID to 44mm ID for Dellorto VHSB carbs to Lambretta TS1 and RB etc as well as Vespa Quattrini, FALC kits etc.
These are the nitrile AF version and they have 1 groove moulded into the rubber.
Product code: LUAF1229
Lambretta & Vespa Carburettor mounting rubber - Stepped, VHSB to TS1/RB
Sales Tax Included