A volume adjustable, manual pipette comprising: an upper pipette body adapted to be held in the hand of a user, and having an axial bore; a plunger shaft assembly mounted in the axial bore of the upper pipette body for reciprocating vertical motion, the plunger shaft assembly comprising: a plunger shaft having a button that extends upward from the upper pipette body and a plunger positioning boss; and a piston holder connected to and extending downward from the button and moving in unison with the button, the plunger shaft and the plunger positioning boss; a pipetting piston operatively coupled to a lower end of piston holder so that the pipetting piston moves in unison with the plunger button and piston holder, and a volume adjustment mechanism having repositionable restraint steps that stop retraction of the plunger positioning boss to set a full stroke length of the plunger shaft and pipetting piston, said volume adjustment mechanism including a series of three rotatable step cylinders (74, 76, 78) that surround the plunger shaft assembly and are manually rotated to set the position of the repositionable restraint steps; wherein each step cylinder (74, 76, 78) has steps with a fixed height; and the height of the steps (94, 98, 102) on each step cylinder (74, 76, 78) is different from the height of the steps on the other step cylinders (74, 76, 78). an upper pipette body adapted to be held in the hand of a user, and having an axial bore; a plunger shaft assembly mounted in the axial bore of the upper pipette body for reciprocating vertical motion, the plunger shaft assembly comprising: a plunger shaft having a button that extends upward from the upper pipette body and a plunger positioning boss; and a piston holder connected to and extending downward from the button and moving in unison with the button, the plunger shaft and the plunger positioning boss; a pipetting piston operatively coupled to a lower end of piston holder so that the pipetting piston moves in unison with the plunger button and piston holder, and a volume adjustment mechanism having repositionable restraint steps that stop retraction of the plunger positioning boss to set a full stroke length of the plunger shaft and pipetting piston, said volume adjustment mechanism including a series of three rotatable step cylinders (74, 76, 78) that surround the plunger shaft assembly and are manually rotated to set the position of the repositionable restraint steps; wherein each step cylinder (74, 76, 78) has steps with a fixed height; and the height of the steps (94, 98, 102) on each step cylinder (74, 76, 78) is different from the height of the steps on the other step cylinders (74, 76, 78). a plunger shaft having a button that extends upward from the upper pipette body and a plunger positioning boss; and a piston holder connected to and extending downward from the button and moving in unison with the button, the plunger shaft and the plunger positioning boss; a pipetting piston operatively coupled to a lower end of piston holder so that the pipetting piston moves in unison with the plunger button and piston holder, and a volume adjustment mechanism having repositionable restraint steps that stop retraction of the plunger positioning boss to set a full stroke length of the plunger shaft and pipetting piston, said volume adjustment mechanism including a series of three rotatable step cylinders (74, 76, 78) that surround the plunger shaft assembly and are manually rotated to set the position of the repositionable restraint steps; wherein each step cylinder (74, 76, 78) has steps with a fixed height; and the height of the steps (94, 98, 102) on each step cylinder (74, 76, 78) is different from the height of the steps on the other step cylinders (74, 76, 78).