While tapping is most commonly observed on electric guitar, it may apply to almost any string instrument, and several instruments have been created specifically to use the method. The Bunker Touch-Guitar (developed by Dave Bunker in 1958) is designed for the technique, but with an elbow rest to hold the right arm in the conventional guitar position. The Chapman Stick (developed in the early 1970s by Emmett Chapman) is an instrument designed primarily for tapping, and is based on the "Free Hands" two-handed tapping method invented by Chapman in 1969 where each hand approaches the fretboard with the fingers aligned parallel to the frets. The Hamatar, Mobius Megatar, Box Guitar, and Solene instruments were designed for the same method. The NS/Stick and Warr Guitar are also built for tapping, though not exclusively. The harpejji is a tapping instrument which is played on a stand, like a keyboard, with fingers typically parallel to the strings rather than perpendicular. All of these instruments use string tensions less than a standard guitar, and low action to increase the strings' sensitivity to lighter tapping.