Jim Dunlop Chrome Steel Slide 220
Chromed Steel slides are perfect for creating the bright, metallic tones preferred by rock, metal and blues style electric guitarists. While sliding, they add a desirable ambience to the sound.

Slide dimensions are listed in millimeters:
Medium Wall:19 x 22 x 60, fits ring size 9

 When playing slide guitar, the string is not pushed down on the fret. The slide lightly pushes the string directly over the desired guitar fret (as opposed to playing next to the fret with your finger)