Dunlop 235 Pyrex Glass Slides have a warmer, thicker tone accentuating the middle harmonics of your sound. One of today"s most popular slides, it"s processed from high-quality Boron Silicate which is heat-treated and annealed to produce a flawless tube. 7/8" inside diameter x 1-1/4" outside diameter x 2-3/4" length.