A multilayer wire-grid polarizer for polarizing light includes a stack of thin film layers disposed over a substrate, including a wire-grid array of elongated metal elements having lengths longer than a wavelength of the light and a period less than half the wavelength of the light. An improved pipette tip that includes the addition of a second elastomeric material and cooperative means for insuring uniform interference and depth of penetration of the pipetter barrel as successive barrels are inserted and ejected. The conductive channel layer is adapted to provide a dual channel.