A slide used around a player's finger can be made with any type of smooth hard material that allows tones to resonate. Different materials cause subtle differences in sustain, timbre, and loudness; glass or metal are the most common choices. Longer slides are used to bridge across all six guitar strings at once, but take away the fretting ability of that finger entirely. A shorter slide allows the fingertip to protrude from the slide and allow that finger to be used to fret.
