The Jim Dunlop 213 Thick Glass Large Bottle Neck Slide. Today's most popular slide for lightining fast licks. Choose the Jim Dunlop 213 Pyrex Glass Slide for a warmer, thicker tone accentuating the middle harmonics of your sound. Today's most popular slide. Processed from high quality Boron Silicate. Heat treated and annealed to produce a flawless tube. The main features of the Jim Dunlop 213 include: Size of 213 is Large 23 x 32 x 69, fits ring size 14 Processed from high quality Boron Silicate The 213 slide creates a warmer, thicker tone accentuating the middle harmonics of your sound