Choose Dunlop Pyrex Glass Slides for a warmer, thicker tone accentuating the middle harmonics of your sound. Dunlop is today's most popular slide. Processed from high quality Boron Silicate. Heat treated and annealed to produce a flawless tube. The Dunlop 210 20mm x 25mm x 60mm, and fits ring size 10.5. For authentic slide tones, Dunlop's your choice!