This is a steel rule for measuring the height of your strings above the fingerboard. You determine the action by measuring from the crown (top) of the 12th fret, to the underside of the string. Lining the gauge up behind the G string allows you to use the measurements and see what your action is.

Action is usually measured in mm - but the gauge also has imperial measurements. It has plenty of other bits of information and measurements too. Things I never use but I don’t know - maybe you’ll find a reason to use them!

I’ve advertised this as a ukulele string action gauge but it is in fact a guitar one - as it’s suitable for anything for frets and strings.

Please note, these can only be sent outside of the UK if ordered with a ukulele, I can’t post them overseas individually.