bottleneck
A glass or metal slide used on the finger for slide guitar, originally made from a broken bottle neck.
In Depth
The term bottleneck refers both to the physical slide and the playing style. Early blues musicians literally broke the necks off glass bottles and used them as slides, giving the technique its name. Modern bottlenecks are precision-manufactured in various materials: glass produces a warm, smooth tone; brass is brighter and louder; ceramic falls between the two. The choice of material significantly affects the tonal character.
Duane Allman used a Coricidin cold medicine bottle as his slide, and after his death, the small glass bottles became collectors' items among guitarists.