These are specially made for Lambretta upgrades in the U.K. from top quality gasket material, with far superior sealing qualities. Specifically used for fuel and oil under pressure unlike 1standard gaskets. 
They have a much larger port transfer areas and outside area to sit on the barrel and casing gasket surfaces, giving better sealing
 
The gasket material is made from aramid and man-made mineral fibres bonded with nitrile rubber. Suitable for sealing out oils and fuels, also water, steam, gases and many chemicals!
Complies with test requirements of BS7531 Grade Y
 
Available in 0.25mm, 0.5mm, 0.75mm and 1.0mm - 0.5mm is standard, please choose from the drop-down menu.
 
Part numbers:
0.25mm - LUTi2500.25
0.5mm - LUTi2500.5
0.75mm - LUTi2500.75
1mm - LUTi2501