These speaker inserts are cut from thick black acrylic and will fit perfectly in front of the speakers on your Metallica pinball machine.  Highly detailed , this skull brings out the attitude that metallica hard rock n roll fans know so well. These inserts look best when backlit with speaker lights to show off the devilish skull design.  The inserts mount behind speaker panel and blend well with the theme.  Easy installation. Sold as a pair.