This is a well made reproduction of a German WWII straight type rubber eye cup for the K98 mauser rifle scope. The eye cup served not only to make shooting more comfortable but also to help reduce the glare from the lens. Yes naturaly this piece is made from a good quality rubber as the original. The opening diameter is 35mm. It is only $2.50 to ship this liner anywhere in the US, Canada, Australia, NZ and most of Asia. Postage within the EU is $1.50, all others pay actual postage.