Ergonomics is a dominant design principle, and it's become apparent to manufacturers that this means making devices customizable for multiple users. Many multichannel models feature rotating tip cone modules 1 and this model, has a moveable trigger 2 to help righties and lefties find a comfortable hand position.

Tip ejection becomes more difficult with increasing channels. Ejection for a 12 channel module can require as much as 100 Newton. That's a lot of work for a thumb motion, but mechanical gearing mechanisms 4 can cut the force necessary to dispose of tips by half.

Various models deal with creating good tip seals differently: by using spring loaded or elastomer tip cones, by employing O-rings, or by working with specially designed disposable tips.

A stepper motor 3 using a lead screw assembly pushes the piston shafts in unison along increments just thousandths of a millimeter.

Pipettors generally work by air displacement. A horizontal bar 5 in the tip cone module controls 8, 12, or 16 pistons simultaneously. Although tip cone modules are removable for many models (for autoclaving), they are not interchangeable.

NOTE: An original version of this article referred to the maker of the Finnpipette Novus as Thermo. It is in fact Thermo Fisher Scientific.