D'Addario's glass guitar slides are made from boron silicate for enhanced durability, smoothness and tone. Perfect for acoustic and electric guitars. This is a small size that's great for players who like to wear their slide on their pinky finger.. The inside diameter measures 11/64 inch, (.64" / 17.0mm I.D.), 1.9 inches long (48.6mm length) with a wall thickness of .16 inch (4.2mm). You need different slides for different sounds to match the mood of your music. This would be a great addition to your arsenal of slide sounds.