A pipette for transferring liquid samples includes a body having a handle and a base. A piston assembly is axially movable in the body. A movable lower stop is placed in the path of the piston assembly to stop the piston to limit the length of an intake stroke and is withdrawn from the path to permit...http://www.google.fr/patents/US6158292?utm_source=gb-gplus-shareBrevet US6158292 - Pipette
