With Schaller's M6 backlocking tuner the string is locked in the shaft by a handy knurled nut located on the rear of the peghead. This results in a low overall height and makes changing strings faster and easier. The string does not need to be wound onto the shaft which means it holds its tuning, perfectly suited to non-locking tremolo systems. This patented locking system prevents strings from notching and breaking, making them the benchmark in locking tuners. Gear ratio 1:18.