Like the original Micro-stella precision regulator of a RLX. Caliber 2130, 3035, 3055, 3135, 3155 (and similar). This precision tools are filled with oil which allows the balance weight to float, providing a great accuracy in reading the graduations located on the index scale. Adjustments can be made either with the movement inside or outside of the watch case. Delivered in a plastic box with detailed user's manual.
Micro-Stella Balance Regulating Wrench