Sealed electronic sensor, highly immune to outside interference and environmental conditions, have been added to each axis of the manipulator arm. Measurements are accurate to 10 microns in all three directions. Movements in all three directions are now monitored by a large, easy-to-read LED display module, with a resolution selectable from 1 mm to 10 microns. A zeroing function allows the user to set a reference point for targeting specific coordinates on the animal's skull for injection, implantation, etc. Calculation of distance measurements via the vernier scales is thus no longer necessary…saving the user valuable time and improving accuracy. The classic design and high quality of our conventional Lab Standard™ manipulators are exactly the same on the new Digital Stereotaxic, with no drift and smooth movements. The Digital Lab Standard™ keeps the custom triple-start lead screws to allow fast positioning, while maintaining consistently smooth movement. The thin cords from the sensors do not interfere with movements, allowing the arm to move freely and be set at any angle. Zeroing Function for Targeting Specific Coordinates -The display of each axis can be "ZERO"ed at any location, making operation simple and straightforward. To target a specific location, start at Bregma, and reset all coordinates to zero. Move the manipulator arm to the desired point and lower the electrode, probe, or micropipette into place. Memory -Target coordinates can be programmed into the memory of the 51900 and 51903 Digital Lab Standard™ Stereotaxics. Versatility of Positioning -The universal joint allows the investigator to angle the probe in either the anterior-posterior or the lateral-medial planes. The improved locking mechanism on the Lab Standard™ Stereotaxic Instruments will hold any angled position without slippage. Of course, it also provides an absolute lock at the vertical position. The manipulator arm may be swiveled out of the way for convenience in installing the animal or performing a procedure, then returned to the same point reliably with the aid of the locking face block above the swivel joint.