Top quality, made in UK, especially for Lambretta upgrades from scratch. 
 
This is a specially made base gasket with the correct stud spacings for the 200/225 block Lambretta engine casing. These have been checked to make sure they are correct. Big surface area around ports for porting. Essential you get the correct base and head gaskets for setting correct port timings and squish height.
5mm thick, for use with bigger crank/con-rods.