Scruggs tuners—now generally called Scruggs-Keith tuners—are special tuners replacing the normal pegs on the B and G strings. They house built in cams and stops that allow the player to change the tuning of the string between two different notes. Earl Scruggs and his imitators devised instrumental numbers that included the sliding effect of using these special tuners to move between successive notes while playing.

Earl's orignial tuners were an extra set of pegs mounted between the existing pegs with an adjustable arm that pushed against the B and D strings, stretching them to a higher preset note. Bill Keith is credited with designing the pegs with the built-in mechanism so there was no need to add an extra set of pegs.

Old Flatt & Scruggs album covers show Earl with his original tuners covered by a small box so other players couldn't see what what was going on and copy that aspect of his music.

I've heard some people refer to banjo players as "de-tuners" but that's not always accurate. <g>

      - Mark