A portion of a video andor audio stream of information is stored in a buffer memory as a plurality of data blocks connected together by a doubly linked list. The first lens group contains at least one positive lens which is primarily arranged in the beam direction, and at least one negative lens, whereby the negative lenses in the first lens group are biconcave or plano-concave lenses. The space between the soldered wires and the connector body are filled with an epoxy. These enzyme containing tips will be used for the transport of very small amounts of enzyme to the sample, where the biochemical reaction takes place. The insert may be a metal insert.