Heathrow Scientific HS120099 Pearl Adjustable Volume Micro Pipette, 0.2 to 20 ul Volume Range, Single Channel, White/Light Purple Internal metal parts for increased accuracy and calibration stability The sleek, ergonomic design and reduced plunger pressure help reduce the chance of Repetitive Stress Injury (RSI), as the pipettes require 2/3 the operation pressure of most standard pipettes Each pipette is tested in accordance with standards and a calibration certificate is supplied Manufactured in accordance with ISO08655 and GLP regulations Volume adjustment and low-force dispensing all in one button for convenience