The lid of a Master-Touch Premium is virtually identical to a normal Weber kettle lid. We don’t make them out of thinner or lighter material.
The reason the lid of a Master-Touch Premium may feel lighter is because the springs in the lid hinge are helping to support some of the weight when opening and closing the lid.
Also, there’s different type of handle on the Master-Touch Premium lid, which does make it slightly lighter than models with the standard handle.