This Dunlop 210 glass slide is a medium guitar slide, made from impact-resistant tempered glass. It features 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. 20 x 25 x 60mm / .79 x .98 x 2.36". Fits ring sizes 10-11.