Choose Dunlop Pyrex Glass Slides for a warmer, thicker tone accentuating the middle harmonics of your sound. Dunlop is creating today's most popular slides. Processed from high quality Boron Silicate, and heat treated and annealed to produce a flawless tube, the 212 is a favorite among musicians around the world! The Dunlop 212 measures in at 17mm x 25mm x 51mm, and fits ring size 7. For authentic slide tones, Dunlop's your choice!