Owl™ D4 Horizontal Electrophoresis System Replacement Parts ExternalOwl D4 Horizontal Electrophoresis System Replacement Parts Replace your UVT Gel Tray, gaskets and external caster with Thermo Scientific Owl D4 Horizontal Electrophoresis System Replacement Parts, for use with the Owl D4 System. System design allows you to run one gel tray (51 samples) or stack two gel trays (102 samples) in the buffer chamber while saving valuable bench space. Each of the (2) U. V. Transmissible (UVT) gel trays, 16 x 17 cm (W x L),