The most traditional of slides are the bottlenecks. The Big Heart Bottleneck Glass Guitar Slide
features a wine bottle lip, flared sides, and a flame polished end. The lip end fits smaller fingers, while the bottom end fits larger fingers.
Glass is a material that's been used for guitar since the very beginning. At Big Heart, they offer everything from recycled wine bottlenecks and medicine bottles to handblown glass slides. Nothing beats glass for high end overtones and a clean but very emotionally resonant sound.