The original Lambretta handlebar gear selector only has the 4 gear positions for the original 4-speed gearbox. These gear changer housings no have precisely marked 5 gear positions to be used in conjunction with 5-speed gearboxes that are currently on the market. 
 
These suit the Italian Li series 1 also the TV and Li series 2 models. They have the shallow slot to take the paddle type gear rod NOT the one with the plastic handlebar bush - please check yours before buying.
 
Please note: these are NOT the CASA ones.