Dunlop Tempered Glass Slides offer a warmer, thicker tone accentuating the middle harmonics of your sound. Processed from high quality boron silicate. Heat treated and annealed for a flawless tube. A warmer, thicker tone that accentuates the middle harmonics of your sound. Processed from high quality Boron Silicate. Heat treated and annealed to produce a flawless tube. Dimensions: 18x22x69mm Ring Size 8