A pipette tip comprising: a circumscribing sidewall with an open interior passage including an interior surface extending along a central longitudinal axis of the pipette tip between an open proximal end and an open distal end of the pipette tip; a first section formed in the interior surface of the circumscribing sidewall distal to the open proximal end, wherein the first section comprises: a cylindrical upper first portion having a first diameter; a cylindrical lower first portion having the first diameter; an annular groove interposed between the cylindrical upper first portion and the cylindrical lower first portion; and a second section comprising a cylindrical surface is formed in the interior surface of the circumscribing sidewall distal to the first section, the second section having a second diameter smaller than the first diameter; a stop shoulder surface is formed in the interior surface of the circumscribing sidewall at an interface of the first section and the second section; a third section comprising a cylindrical surface is formed in the interior surface of the circumscribing sidewall distal to the second section, the third section having a third diameter smaller than the second diameter; a sealing seat (266, 268, 270) is formed in the interior surface of the circumscribing sidewall and interposed between the second section and the third section, the sealing seat (266, 268, 270) comprising: an upper annular sealing seat surface edge at an interface with the second section; a lower annular sealing seat surface edge at an interface with the third section; a sealing seat surface interposed between the upper annular sealing seat surface edge and the lower annular sealing seat surface edge; wherein the upper annular sealing seat surface edge is greater in diameter than the lower annular sealing seat surface edge; and wherein the sealing seat surface is in the form of a circumferential upwardly facing tooth edge surface; and at least one frustoconical section (274, 275) formed in the interior surface of the circumscribing sidewall and between the third section and the open distal end. a circumscribing sidewall with an open interior passage including an interior surface extending along a central longitudinal axis of the pipette tip between an open proximal end and an open distal end of the pipette tip; a first section formed in the interior surface of the circumscribing sidewall distal to the open proximal end, wherein the first section comprises: a cylindrical upper first portion having a first diameter; a cylindrical lower first portion having the first diameter; an annular groove interposed between the cylindrical upper first portion and the cylindrical lower first portion; and a second section comprising a cylindrical surface is formed in the interior surface of the circumscribing sidewall distal to the first section, the second section having a second diameter smaller than the first diameter; a cylindrical upper first portion having a first diameter; a cylindrical lower first portion having the first diameter; an annular groove interposed between the cylindrical upper first portion and the cylindrical lower first portion; and a second section comprising a cylindrical surface is formed in the interior surface of the circumscribing sidewall distal to the first section, the second section having a second diameter smaller than the first diameter; a stop shoulder surface is formed in the interior surface of the circumscribing sidewall at an interface of the first section and the second section; a third section comprising a cylindrical surface is formed in the interior surface of the circumscribing sidewall distal to the second section, the third section having a third diameter smaller than the second diameter; a sealing seat (266, 268, 270) is formed in the interior surface of the circumscribing sidewall and interposed between the second section and the third section, the sealing seat (266, 268, 270) comprising: an upper annular sealing seat surface edge at an interface with the second section; a lower annular sealing seat surface edge at an interface with the third section; a sealing seat surface interposed between the upper annular sealing seat surface edge and the lower annular sealing seat surface edge; wherein the upper annular sealing seat surface edge is greater in diameter than the lower annular sealing seat surface edge; and wherein the sealing seat surface is in the form of a circumferential upwardly facing tooth edge surface; and an upper annular sealing seat surface edge at an interface with the second section; a lower annular sealing seat surface edge at an interface with the third section; a sealing seat surface interposed between the upper annular sealing seat surface edge and the lower annular sealing seat surface edge; wherein the upper annular sealing seat surface edge is greater in diameter than the lower annular sealing seat surface edge; and wherein the sealing seat surface is in the form of a circumferential upwardly facing tooth edge surface; and at least one frustoconical section (274, 275) formed in the interior surface of the circumscribing sidewall and between the third section and the open distal end.