This mouthpiece allows you to fully enjoy the rich, mellow, and lustrous sound unique to crystal. Also, crystal doesn't deteriorate, so it's great that it can be used semi-permanently unless it breaks. There is some dirt on the patch placement area, but it won't be noticeable once a patch is applied, and there are no scratches or stains in other areas. I hope someone who understands this will enjoy using it. Opening: 1.10mm (5RV Lyre is 1.09+)