This is a well made reproduction of a German WWII flared type rubber eye cup for the MGZ sight that was used on the lafette mount. Yes naturally this piece is made from a good quality rubber as the original. The opening diameter is 28-29 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.