There are two distinct styles of slide playing - open, where you let all the strings sing, and damped, where you use a finger behind the slide to damp the strings you aren't playing. For open playing, there are three main tunings - the G tuning described above (which is also called Spanish), open D (dadf#ad),also called Vestapol, and C (cgcgce). Damped playing is usually employed for solo work, and can be used in any tuning - even standard tuning, as the main purpose is to utilise the sound of sliding on to a note, rather than anything else.