This is a well made reproduction of a German WWII flared type rubber eye cup for the MGZ 40 sight that was used on the lafette mount. The MGZ 40 sight was introduced after the MGZ sight and allowed the shooter to have their head lower and thus less exposed when aiming through the sight Yes naturally this piece is made from a good quality rubber as the original. The opening diameter is 24-23 mm. It is only $3.00 to ship this liner anywhere in the US, Canada, Australia, NZ and most of Asia. Postage within the EU is $2.00, all others pay actual postage.