For nearly 25 years, doctors and technicians have trusted Tono- Pen® tonometers for their accuracy, reliability, and ease of use. Other handheld tonometers have come and gone, but none have stood the test of time like the Reichert Tono-Pen®. Choose from the original Tono-Pen® XL model or the new award-winning, ergonomic Tono-Pen AVIA®, which does not require daily calibration.