Schaller Locking Tremolo Chrome 370 with R3 Locking Nut. All tremolo systems are supplied complete with nut (please choose R1-R10, see under "guidelines"), string retainers, springs, height adjustment screws, Allen wrench and mounting accessories. Along with the tremolos and nuts, Schaller supplies wood screws and steel screws / Allen screws, so you can choose how to attach the nuts yourself i.e. either from the top or from underneath. The nuts are also specially designed so that you can use wood or steel screws without carrying out any modifications whatsoever.